Tumor-targeting monoclonal antibodies to FZD10  and uses thereof

ABSTRACT

The present invention relates to an antibody or a fragment thereof which is capable of binding to a Frizzled homologue 10 (FZD10) protein, such as a mouse monoclonal antibody, a chimeric antibody and a humanized antibody. Also, the present invention relates to a method for treating and/or preventing FZD10-associated disease; a method for diagnosis or prognosis of FZD10-associated disease; and a method for in vivo imaging of FZD10 in a subject.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority on U.S. Provisional Application No. 60/815,257 filed on Jun. 21, 2006. The entire contents of the above application are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to an antibody or a fragment thereof which is capable of binding to a Frizzled homologue 10 (FZD10) protein, such as a mouse monoclonal antibody, a chimeric antibody and a humanized antibody. Also, the present invention relates to a method for treating and/or preventing FZD10-associated disease; a method for diagnosis or prognosis of FZD10-associated disease; and a method for in vivo imaging of FZD10 in a subject.

BACKGROUND OF THE INVENTION

Monoclonal antibodies against cancer-specific molecules have been proved to be useful in cancer treatment (Harris, M. (2004). Lancet Oncol, 5, 292-302.). In addition to successful examples of clinical application of the humanized or chimeric antibodies such as trastuzumab (Baselga, J. (2004). Oncology, 61, Suupl 2 14-21.), rituximab (Maloney, D. G., et al. (1997). Blood, 90, 2188-95.) and bevacizumab (Ferrara, N., et al. (2004). Nat Rev Drug Discov, 3, 391-400.) for breast cancer, malignant lymphoma and colon cancer, a number of monoclonal antibodies against other molecular targets are in development and being evaluated their anti-tumor activities. These monoclonal antibodies are expected to provide a hope to patients having tumors that have no effective treatment. One of the other important issues for these monoclonal antibodies is achievement of selective therapeutic effects to cancer cells without severe toxicity due to their specific reaction to cells expressing target molecules (Crist, W. M., et al. (2001). J Clin Oncol, 19, 3091-102.; Wunder, J. S., et al. (1998). J Bone Joint Surg Am, 80, 1020-33.; Ferguson, W. S. and Goorin, A. M. (2001). Cancer Invest, 19, 292-315.).

Among soft tissue sarcomas, osteosarcoma, Ewing's sarcoma and rhabdomyosarcoma are sensitive to chemotherapy and these diseases can be well managed by chemotherapy. On the other hand, spindle cell sarcomas are resistant to chemo- and radiotherapy and patients with them usually exhibit poor prognosis. For synovial sarcoma (SS), surgical treatment is effective for patients at an early stage, but no effective therapeutic drug is available to those at an advanced stage. Hence, development of novel therapeutic modalities is expected to ‘improve patients’ prognosis better.

Genome-wide gene expression analysis in tumors provides the useful information to identify the new molecular targets for development of novel anticancer drugs and tumor markers. In previous study, the present inventors have analyzed gene-expression profile of several soft tissue sarcomas using genome-wide cDNA microarray consisting of 23,040 genes and demonstrated that Frizzled homologue 10 (FZD10) (GenBank Accession NOs. AB027464 (SEQ ID NO:1) and BAA84093 (SEQ ID NO:2)) was up-regulated specifically and frequently in SSs (Nagayama, S., et al. (2002) Cancer Res, 62, 5859-66.; and WO2004/020668). FZD10 gene product is a member of Frizzled family and a putative WNT signal receptor (Koike, J., et al. (1999). Biochem Biophys Res Commun, 262, 39-43.). Further analysis showed that FZD10 is expressed specifically in SS, and at no or hardly-detectable level in other normal organs except the placenta, suggesting that therapeutics targeting this molecule would cause no or little adverse reaction (Nagayama, S., et al. (2002). Cancer Res, 62, 5859-66.). RNAi experiments implicated that FZD10 was significantly involved in the tumor growth of SS (WO2006/013733). Furthermore, the present inventors generated the rabbit polyclonal antibody against the extracellular domain of FZD10 (FZD10-ECD), and found that this antibody had antitumor activity in mouse xenograft model of SS (Nagayama, S., et al. (2005). Oncogene, 24, 6201-12.; and WO2005/004912). Together, the antibody therapy against FZD10 could be expected to improve the clinical outcome of SS.

SUMMARY OF THE INVENTION

Hereinbelow, it is reported that generation of the murine monoclonal antibodies against FZD10 by means of cell-immunization method for possible clinical application. In vivo tumor-binding activity of these antibodies was evaluated using fluorescent in vivo imaging system with near-infrared fluorescence in addition to the conventional method with radionuclides. Here, we reveal the binding specificity of anti-FZD10 monoclonal antibodies both in vitro and in vivo as well as internalization of these antibodies in the cells expressing FZD10, and found that SYO-1-bearing xenograft mice treated with a single tail vain of ⁹⁰Y-labeled anti-FZD10 Mab at 100 μCi dose was observed significant antitumor effect.

Based on the above findings, the present inventors concluded that the murine monoclonal antibodies against FZD10 have therapeutic potential in the treatment and diagnosis of SS and other FZD10-overexpressing tumors.

Therefore, in the first aspect, the present invention provides an antibody or a fragment thereof, which comprises an H (heavy) chain V (variable) region comprising a complementarity determining region (CDR) having the amino acid sequences shown in SEQ ID NOs: 15, 17 and 19 or a CDR functionally equivalent thereto and an L (light) chain V region comprising a CDR having the amino acid sequences shown in SEQ ID NOs: 23, 25 and 27 a CDR functionally equivalent thereto, and which is capable of binding to a Frizzled homologue 10 (FZD10) protein or a partial peptide thereof.

In one embodiment, the antibody or fragment thereof is selected from the group consisting of a mouse antibody, a chimeric antibody, a humanized antibody, an antibody fragment, and single-chain antibody.

In a preferred embodiment, the antibody is a mouse antibody. Preferably, the mouse antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 57 and/or an L chain having the amino acid sequence shown in SEQ ID NO: 59. For example, the mouse antibody can be produced by the hybridoma clone 92-13 (FERM BP-10628).

In an alternative preferred embodiment, the antibody is a chimeric antibody. Preferably, the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO: 13, for example, the chimeric antibody may comprise an H chain having the amino acid sequence shown in SEQ ID NO: 46. Preferably, the chimeric antibody comprises an L chain V region having the amino acid sequence shown in SEQ ID NO: 21, for example, the chimeric antibody may comprise an L chain having the amino acid sequence shown in SEQ ID NO: 48.

More preferably, the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO: 13 and an L chain V region having the amino acid sequence shown in SEQ ID NO: 21. For example, the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 46 and an L chain having the amino acid sequence shown in SEQ ID NO: 48.

In one embodiment, the chimeric antibody further comprises a human antibody C (constant) region.

In an alternative preferred embodiment, the antibody is a humanized antibody. In one embodiment, the humanized antibody further comprises a human antibody FR (framework) region and/or a human antibody C region.

In the second aspect, the present invention provides an antibody or a fragment thereof, which comprises an H (heavy) chain V (variable) region comprising a complementarity determining region (CDR) having the amino acid sequences shown in SEQ ID NOs: 31, 33 and 35 or a CDR functionally equivalent thereto and an L (light) chain V region comprising a CDR having the amino acid sequences shown in SEQ ID NOs: 39, 41 and 43 or a CDR functionally equivalent thereto, and which is capable of binding to a Frizzled homologue 10 (FZD10) protein or a partial peptide thereof.

In one embodiment, the antibody or fragment thereof is selected from the group consisting of a mouse antibody, a chimeric antibody, a humanized antibody, an antibody fragment, and single-chain antibody.

In a preferred embodiment, the antibody is a mouse antibody. Preferably, the mouse antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 61 and/or an L chain having the amino acid sequence shown in SEQ ID NO: 63. For example, the mouse antibody can be produced by the hybridoma clone 93-22 (FERM BP-10620).

In an alternative preferred embodiment, the antibody is a chimeric antibody. Preferably, the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO: 29, for example, the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 50. Preferably, the chimeric antibody comprises an L chain V region having the amino acid sequence shown in SEQ ID NO: 37, for example, the chimeric antibody comprises an L chain having the amino acid sequence shown in SEQ ID NO: 52.

More preferably, the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO: 29 and an L chain V region having the amino acid sequence shown in SEQ ID NO: 37. For example, the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 50 and an L chain having the amino acid sequence shown in SEQ ID NO: 52.

In one embodiment, the chimeric antibody further comprises a human antibody C (constant) region.

In an alternative preferred embodiment, the antibody is a humanized antibody. In one embodiment, the humanized antibody further comprises a human antibody FR (framework) region and/or a human antibody C region.

In yet an alternative embodiment, the antibody or fragment thereof can be labeled with a radioisotope label or a fluorescent label. Such radioisotope label includes ⁹⁰yttrium (⁹⁰Y), ¹²⁵iodine (¹²⁵I) and ¹¹¹indium (¹¹¹In).

In the third aspect, the present invention provides a hybridoma clone 92-13 (FERM BP-10628) which produces the mouse monoclonal antibody 92-13.

In the forth aspect, the present invention provides a hybridoma clone 93-22 (FERM BP-10620) which produces the mouse monoclonal antibody 93-22.

In the fifth aspect, the present invention provides a method for treating or preventing a disease that is associated with Frizzled homologue 10 (FZD10) in a subject, comprising administering to the subject an effective amount of the antibody or fragment above. In one embodiment, the disease that is associated with FZD10 is selected from synovial sarcoma (SS), colorectal cancer, gastric cancer, chronic myeloid leukemia (CML), and acute myeloid leukemia (AML).

In the sixth aspect, the present invention provides a method for diagnosis or prognosis of a disease that is associated with Frizzled homologue 10 (FZD10) or of a predisposition to develop the disease in a subject, comprising

(a) contacting a sample or a specimen from the subject with the antibody or fragment above;

(b) detecting the FZD10 protein in the sample or specimen; and

(c) judging whether or not the subject suffers from or is at risk of developing the disease based on the relative abundance of the FZD10 protein compared to a control.

In one embodiment, the disease that is associated with FZD10 is selected from synovial sarcoma (SS), colorectal cancer, gastric cancer, chronic myeloid leukemia (CML), and acute myeloid leukemia (AML).

In the seventh aspect, the present invention provides a method for in vivo imaging of Frizzled homologue 10 (FZD10) protein in a subject, comprising administering to the subject an effective amount of the antibody or fragment above.

In the eighth aspect, the present invention provides a pharmaceutical composition for treating or preventing a disease associated with Frizzled homologue 10 (FZD10), comprising the antibody or fragment above and a pharmaceutically acceptable carrier or excipient.

In the ninth aspect, the present invention provides a kit for diagnosis or prognosis of a disease associated with Frizzled homologue 10 (FZD10), comprising the antibody or fragment above.

In the tenth aspect, the present invention provides a pharmaceutical composition for in vivo imaging of Frizzled homologue 10 (FZD10) protein, comprising the antibody or fragment above.

In the eleventh aspect, the present invention provides use of the antibody or fragment above in the manufacture of a kit for diagnosis or prognosis of a disease associated with Frizzled homologue 10 (FZD10).

In the twelfth aspect, the present invention provides use of the antibody or fragment above in the manufacture of a composition for prevention or treatment of a disease associated with Frizzled homologue 10 (FZD10).

The term “disease that is associated with FZD10” (FZD10-associated disease) refers to a disease that is associated with over-expression of FZD10 protein. Such diseases include, but are not limited to, synovial sarcoma (SS), colorectal cancer, gastric cancer, chronic myeloid leukemia (CML), and acute myeloid leukemia (AML).

The term “fragment” means any antibody fragment that can be prepared from the antibody against FZD10 protein and contains defined CDRs. Such fragment includes, but not limited to, Fab fragment, F (ab′)₂ fragment, and Fv fragment.

The term “modified antibody” means any antibody that can be derived from the antibody against FZD10 and contains defined CDRs. Such modified antibody includes, but not limited to, a PEG-modified antibody. The antibody fragment or modified fragment can be readily recognized by a person skilled in the art and produced by using any methods known in the art.

The term “subject” herein refers to a subject who has suffered from FZD10-associated disease and also a subject suspected to have FZD10-associated disease. The subject in the present invention may be animals including mammals and avian animals. For example, mammals may include humans, mice, rats, monkeys, rabbits, and dogs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a to 1 f show characterization of binding specificity for two anti-FZD10 monoclonal antibodies.

FIG. 1 a shows flow-cytometric analysis of the four antibodies, 39-2 and 39-10 (disclosed in WO2005/004912), 92-13 and 93-22, using five SS lines (SYO-1, YaFuSS, HS-SY-2, Fuji and 1973/99) and one colon-cancer cell line (LoVo). Solid lines show the fluorescent intensity detected by each mAbs; broken lines depict the fluorescent intensities of cells incubated with non-immunized mouse IgG as a negative control.

FIG. 1 b shows semi-quantitative RT-PCR of FZD10 in the same tumor-cell lines as used in FIG. 1 a. Expression of β2-microglobulin gene (β2MG) served as an internal control.

FIG. 1 c shows flow-cytometric analysis of 92-13 (top panels) and 93-22 (lower panels) against exogenous FZD10 were indicated. Colon cancer cell line, SNU-C5 was transfected with pCAGGS empty vector (left panels) or pCAGGS-FZD10-myc/His (right panels) and analyzed 48 hours after transfection. Solid lines show the fluorescent intensity detected by each mAbs; broken lines depict the fluorescent intensities of cells incubated with non-immunized mouse IgG as a negative control.

FIG. 1 d shows binding of ¹²⁵I-labeled 39-10, 39-2, 92-13 and 93-22 to normal human blood cells. Radio-labeled Mabs were incubated with each normal human fresh blood of three individuals (A, B and C) in the absence (open bar) or presence (closed bar) of non-labeled identical antibodies.

FIG. 1 e shows binding activity of ¹²⁵I-labeled Mabs. A constant amount of radio-labeled Mabs was incubated with SYO-1 cell and increasing amount of non-labeled antibodies. The percent radioactivity bound to cells was plotted against the amount of non-labeled antibody. Closed circle; 92-13, Open circle; 93-22.

FIG. 1 f shows flow-cytometric analysis of self-block and cross-block. Alexa-488-labeled 92-13 (Top panels) and 93-22 (Lower panels) were incubated with SYO-1 cell in (i) PBS, or in the presence of 100 μg of (ii) non-labeled 92-13 and (iii) non-labeled 93-22. Shaded histogram show the fluorescent intensity detected by each Alexa488-labeled Mabs; broken lines depict the fluorescent intensities of cells incubated with PBS as a negative control.

FIG. 2 shows immunohistochemical analyses in SS and normal human frozen tissue sections with no antibody (a, d, g, j, and m), 92-13 (b, e, h, k, and n) and 93-22 (c, f, i, l, and o). (a-c), synovial sarcoma; (d-f), kidney; (g-i), liver, (j-l), heart; (m-o), brain. Original magnification: ×100.

FIG. 3 shows biodistribution of ¹¹¹In-labeled and ¹²⁵I-labeled antibodies. 10 kBq of (a), ¹¹¹In-labeled 92-13, (b), ¹²⁵I-labeled 92-13, (c), In-labeled 93-22 and (d), ¹²⁵I-labeled 93-22 were injected intravenously into SYO-1 tumor bearing BALB/c nude mice. The organs and tumor were dissected at one hour (open bar), 24 hours (hatched bar) and 48 hours (closed bar), and the radioactivities were measured. The data shown is the representative data in two independent experiments.

FIG. 4 a shows in vivo fluorescence imaging of SYO-1 tumor-bearing mice after injection of Alexa 647-labeled 92-13 or 93-22. Fluorescence-labeled Mabs were administered at a dose of 20 μg per mouse intraperitoneally. All fluorescence images were acquired with a 60-second exposure time (f/stop=2) before injection, immediately after injection (0 hour), 24, 48 and 96 hours. The arrows indicate the position of the tumor. S.C. tumor is located in dorsal for 92-13 (top panels) and in trunk for 93-22 (lower panels). Fluorescence signal from Alexa647 was pseudo-colored according to the color bar indicated on right. In 93-22 (lower panel), the arrowheads indicate the position of injection.

FIGS. 4 b and 4 c show representative images of dissected organs and tumors from mice shown in FIGS. 4 a, 4 b; 92-13, and 4 c; 93-22. 1, SYO-1 tumor; ii, liver; iii, spleen; iv, kidney; v, pancreas; vi, colon.

FIG. 5 a shows in vivo fluorescence imaging of LoVo tumor-bearing mice after injection of Alexa647-labeled 92-13 or 93-22. Fluorescence-labeled Mabs were administered as FIG. 4. All fluorescence images were acquired with a 60-second exposure time (f/stop=2) immediately after injection (0 hour), 48, 72, 96 and 120 hours (h). Arrow indicates the position of the tumor. S.c. tumor is located in right forearm both for 92-13 (Top panels) and 93-22 (lower panels).

FIGS. 5 b and 5 c show representative images of dissected organs and tumors of mice shown in FIGS. 5 a. 5 b; 92-13 and 5 c; 93-22. i, LoVo tumor; ii, liver; iii, spleen; iv, kidney; v, pancreas; vi, colon.

FIG. 6 shows internalization of 92-13 and 93-22 was assessed by confocal microscopy. Cells were treated with PBS (a, d, and g), 50 μg/ml of 92-13 (b, e, and h) or 93-22 (c, f, i) for 3 hours in 37° C., 5% CO₂. Antibodies bound to the cell surface were acid-stripped with 0.1M glycine buffer (pH2.5). Cells were fixed, permeabilized and then blocked with 3% BSA. Intracellular antibodies were detected with goat anti-mouse IgG-Alexa488 and nucleus was stained with DAPI. (a-c), SYO-1; (d-f), YaFuSS; (g-i) Lovo.

FIG. 7 shows the effect of ⁹⁰Y-labeled 92-13 on tumor growth. When tumors were established (0.4-2.7 cm³), mice were given a single tail vain of 100 μCi of ⁹⁰Y-labeled 92-13.

FIG. 8 shows both chimeric 92-13 and 93-22 induced ADCC specifically to the FZD10-overexpressing SYO-1 cells. 1 μg/ml of chimeric 93-22 antibody (ch93-22) or chimeric 92-13 antibody (ch92-13) at various Effector:Target ratio. PBMC from various donors were used as Effector cell; (a), (c) ADCC of chimeric 92-13 against SYO-1 cell with five healthy human PBMC donors. (b), (d) ADCC of chimeric 93-22 against LoVo cell with two healthy human PBMC donors. Quantification of cytotoxity with LDH activity is described in (Nagayama, S., et al. Oncogene, 24, 6201-12.).

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Frizzled homologue 10 (FZD10) is a member of Frizzled family, which is a receptor of Wnt signaling. As described hereinbelow, we successfully established murine monoclonal antibodies and chimeric antibodies against FZD10 protein that may be useful for medical use.

The murine monoclonal FZD10-sepcific antibodies (92-13 and 93-22 Mabs) are established by immunizing mice with FZD10-transfected cells. Both 92-13 and 93-22 Mabs were shown to have specific binding activity against FZD10 in SS cell line, SYO-1 cells and FZD10-transfected COS7 cells by using flow cytometry (FACS) analysis. To validate the specific binding activity of those antibodies in vivo, the present inventors injected fluorescent-labeled Mabs intraperitoneally or intravenously into the mice carrying SS xenografts and found that these Mabs were bound to the FZD10-expressing tumors, but not to any other normal mouse tissues by the use of the in vivo fluorescent imaging system and radioactivities. Subsequent immunohistochemical analyses with the Mabs confirmed an absence or hardly-detectable level of FZD10 protein in normal human organs except the placenta. Furthermore, interestingly the present inventors found that the Mabs were internalized into the SS cell line, SYO-1, but not into FZD10-negative cell line, LoVo using confocal laser scanning microscopy. Surprisingly, SYO-1-bearing xenograft mice treated with a single tail vain of ⁹⁰Y-labeled anti-FZD10 (92-13) Mab at 100 μCi dose was observed significant antitumor effect. Taken together, we conclude that these specific Mabs against FZD10 could be utilized as the novel diagnostic marker or treatment of SS with minimal or no risk of adverse reactions.

Due to their complicated protein structure, it is often very difficult to generate antibodies against seven-transmembrane proteins. In previous study, the present inventors demonstrated that FZD10 formed homo-oligomer (Nagayama, S., et al. (2005). Oncogene, 24, 6201-12.). After failure of multiple attempts to generate anti-FZD10 monoclonal antibodies that could recognize a native form of FZD10 by the use of full-length or partial recombinant FZD10 proteins, we finally applied to immunization by injection of living COS-7 cells overexpressing FZD10 into the foot-pad of Balb/c-mice and successfully obtained the two hybridomas producing anti-FZD10 antibodies that had an ability to recognize the native FZD10 form in living cells by FACS analysis. Since those antibodies did not detect FZD10 protein in western blotting, the present inventors assume that those Mabs recognize the tertiary structure of FZD10.

To investigate the in vivo distribution of 92-13 and 93-22 Mabs, the present inventors applied two methods; one based on the radionuclide modalities using ¹²⁵I and ¹¹¹In-labeled antibodies, and the other based on the fluorescence imaging using near-infrared-labeled (Alexa647) antibodies. Near-infrared fluorescent, mostly indocyanine dye, is now widely used in the in vivo imaging for diagnostic purpose because the light of this wavelength penetrates living tissue quite efficiently (Chen, X., et al. (2004). Cancer Res, 64, 8009-14.). The results obtained two approaches were very concordant and indicated that 92-13 and 93-22 bound to SYO-1 tumor cells, but not to other normal tissues. To confirm whether those antibodies can be applied for clinical use, the present inventors further examined the binding activity of antibodies against normal blood cells. The binding activity of ¹²⁵I-labeled 92-13 and 93-22 against normal human blood cells were undetectable in all of three individual donors (FIG. 1 d). These results were consistent with those of FACS analysis using human peripheral blood mononuclear cell (data not shown), suggesting clinical applicability of these two antibodies with little possibility of adverse effect to SS patients because of very specific binding affinity to the FZD10 molecule. Furthermore, in vitro experiments using confocal microscopy reveled that the specific binding of 92-13 and 93-22 Mabs to cell-surface FZD10 induced the internalization of the antibodies (FIG. 6). As described previously (Stein, R., et al. (2001). Criti Rev Oncol Hematol, 39, 173-80.; Stein, R., et al. (2005). Clin Cancer Res, 11, 2727-34.), if labeled Mabs is internalized after binding, ¹²⁵I-labeled antibody is metabolized in the lysosomes and diffused from target tumor cells where ¹¹¹In-labeled antibody remains in the lysosomes. As observed in FIG. 3, the radioactivities of ¹¹¹In-labeled antibody and ¹²⁵I-labeled antibody in tumors were significantly different (FIG. 3, a and b, c and d). These findings suggest that 92-13 (and 93-22) Mabs can specifically internalize into the SS cells via FZD10 protein.

When antibodies are applied to cancer therapy, the following three mechanisms are thought to exert the anti-tumor activity; (i) in case that the target molecule is involved in growth enhancement, neutralization of antibodies would block the growth signal transduction and then suppress the growth of tumor cells; (ii) The second possibility is the effecter activities to induce antibody-dependent cell-mediated cytotoxity (ADCC) or complement-dependent cytotoxity (CDC). (iii) The third case is radionuclides or antitumor drug that is conjugated to antibodies and is delivered to the target tumor cells effectively. Although the present inventors previously demonstrated that the target molecule FZD10 is involved in the SS tumor growth, neither Mabs 92-13 nor 93-22 showed the neutralizing effect in vitro when added to the cell culture media (data not shown) or in vivo when injected to the tumor-bearing mice (data not shown).

Conjugating radionuclide or anti-cancer drug to antibodies such as Zevalin (anti-CD20 antibody conjugated with ⁹⁰yttrium) and Mylotarg. (anti-CD33 antibody conjugated with calicheamicin), has been proven to be highly effective to confer cytotoxity to the antibodies (Wiseman, G. A. and Witzig, T. E. (2005). Cancer Biother Radiopharm, 20, 185-8.; van der Velden, V. H., et al. (2001). Blood, 97, 3197-204.; Carter, P. (2001). Nat Rev Cancer, 1, 118-29.). Mylotarg exerts its antitumor activity by releasing antitumor drug, calicheamicin within the cancer cell after it was internalized (van der Velden, V. H., et al. (2001). Blood, 97, 3197-204.). In the Examples, for therapeutic experiments, ⁹⁰yttrium-DTPA-92-13 conjugate was generated and its antitumor activity was investigated. In mouse xenograft model, tumors quickly diminished after treatment of ⁹⁰yttrium-DTPA-92-13 (FIG. 7). Noticeably, the tumors including larger volume (>1 cm³) of tumor showed no refraction until 34 days after administration and no strong toxicity was observed. Since anti-FZD10 antibodies 92-13 and 93-22 were likely to be effectively internalized into antigen-positive cells as shown in FIG. 6, conjugation of anti-cancer drug to both Mabs 92-13 and 93-22 is also expected to exert the high anti-cancer effect to SS cells. Referring to the effector activity, both chimeric 92-13 and 93-22 induced ADCC specifically to the FZD10-overexpressing SYO-1 cells (FIG. 8, a and c), but not to the FZD10-negative LoVo cells (FIG. 8, b and d). Particularly, chimeric 92-13 showed higher induction of cytotoxity as compared with chimeric 93-22, however, their activity depends on effector cell donor, possibly caused by polymorphism of Fc receptor. In conclusion, the present inventors successfully produced monoclonal antibodies which were able to bind specific to FZD10 on FZD10-overexpressing tumor cells in vitro and in vivo. Together, the present inventors are confident that anti-FZD10 monoclonal antibodies have great potential for development of novel drug therapies for treatment of SS and other tumors that over-express FZD10.

1. Production of an Antibody

Antibodies that can be used in the present invention specifically react against an FZD10 protein derived from an FZD10-associated disease. The term “antibody” used herein means an antibody molecule as a whole, or its fragments such as Fab fragments, F(ab′)₂ fragments and Fv fragments, which can bind to the protein or its partial peptides as the antigen. The antibody can be either a polyclonal antibody or a monoclonal antibody. It can also be a humanized or chimeric antibody, or a single chain Fv (scFv) antibody. The antibodies (polyclonal antibodies and monoclonal antibodies) for use in the present invention can be prepared, for example, by the following process.

(I) Monoclonal Antibody

Initially, an antigen is prepared for the production of an antibody useful in the present invention. FZD10 protein or its partial peptide can be used as an immunogenic protein. Alternatively, a cell expressing FZD10 protein or its partial peptide can also be used as an immunogen. The amino acid sequence of FZD10 protein used as the immunogen in the present invention and the cDNA sequence encoding the protein are publicly available in GenBank as Accession Nos. BAA84093 (SEQ ID NO: 1) and AB027464 (SEQ ID NO: 2), respectively. The FZD10 protein or its partial peptide for use as the immunogen can be synthetically prepared according to a procedure known in the art such as a solid-phase peptide synthesis process, using the available amino acid sequence information. The partial peptides of FZD10 protein include, but are not limited to, a peptide containing residues 1-225 of the amino acid sequence shown in SEQ ID NO: 1, which corresponds to the N-terminal extracellular domain of FZD10 protein (FZD10-ECD).

The protein or its partial peptide, or the cell expressing them can be prepared by using the sequence information of cDNA encoding FZD10 protein or its partial peptide according to a known gene recombination procedure. The production of the protein or its partial peptide as well as the cell expressing them according to such a gene recombination procedure will be illustrated below.

A recombinant vector for the production of protein can be obtained by linking the above cDNA sequence to an appropriate vector. A transformant can be obtained by introducing the recombinant vector for the production of protein into a host so that the target FZD10 protein or its partial peptide can be expressed.

As the vector, a phage or plasmid that is capable of autonomously replicating in a host is used. Examples of a plasmid DNA include pCAGGS, pET28, pGEX4T, pUC118, pUC119, pUC18, pUC19, and other plasmid DNAs derived from Escherichia coli; pUB110, pTP5, and other plasmid DNAs derived from Bacillus subtilis; and YEp13, YEp24, YCp50 and other plasmid DNAs derived from yeast. Examples of a phage DNA include lambda phages such as λgt11 and λZAP. In addition, animal virus vectors such as retrovirus vector and vaccinia virus vector can be used, and insect virus vectors such as baculovirus vector can also be used.

The DNA encoding the FZD10 protein or its partial peptide (hereinafter referred to as FZD10 DNA) is inserted into the vector, for example, by the following method. In this method, purified DNA is cleaved by an appropriate restriction enzyme and inserted into a restriction enzyme site or a multi-cloning site of an appropriate vector DNA to ligate into the vector.

In addition to a promoter and the FZD10 DNA, any of enhancers and other cis elements, splicing signals, poly A addition signals, selective markers, ribosome binding site (RBS), and other elements can be ligated into the recombinant vector for the production of protein for use in mammalian cells, if desired.

For ligating the DNA fragment to the vector fragment, a known DNA ligase can be used. The DNA fragment and the vector fragment are annealed and ligated, thereby producing a recombinant vector for the production of a protein.

The host for use in transformation is not specifically limited as long as it allows the FZD10 protein or its partial peptide to be expressed therein. Examples of the host include bacteria, for example, E. coli, and Bacillus; yeast, for example, Saccharomyces cerevisiae; animal cells, for example, COS cells, Chinese Hamster Ovary (CHO) cells, and insect cells.

For example, when a bacterium is used as the host, the recombinant vector for the protein production should preferably be capable of autonomously replicating in the host bacterium and comprise a promoter, a ribosome binding site, the FZD10 DNA, and a transcription termination sequence. The recombinant vector may further comprise a gene for regulating the promoter. An example of Escherichia coli includes Escherichia coli BRL, and an example of Bacillus is Bacillus subtilis. Any promoter that can be expressed in the host such as Escherichia coli can be used herein.

The recombinant vector can be introduced into the host bacterium by any procedures known in the art. Such procedures include, for example, a method using calcium ions and an electroporation. When yeast cell, an animal cell, or an insect cell is used as the host, a transformant can be produced according to a known procedure in the art, and then the FZD10 protein or its partial peptide can be produced in the host (transformant).

The FZD10 protein or its partial peptide for use as the immunogen in the present invention can be obtained from a culture of the above-generated transformant. The “culture” refers to any of culture supernatant, cultured cells, cultured microorganisms, and homogenates thereof. The transformant is cultured in a culture medium by a conventional process of culturing a host.

The culture medium for culturing the transformant obtained by using Escherichia coli, yeast, or other microorganisms as the host can be either a natural medium or a synthetic medium, as long as it comprises a carbon source, nitrogen source, inorganic salts, and other components utilizable by the microorganism and enables the transformant to grow efficiently.

The transformant is generally cultured by shaking culture or aeration culture with stirring under aerobic conditions at 25° C. to 37° C. for 3 to 6 hours. During culturing, pH is held at a level near neutrality by adjustment with, for example, an inorganic or organic acid, and an alkaline solution. During culturing, antibiotics such as ampicillin or tetracycline may be added to the medium according to the selective marker inserted into the recombinant expression vector, if necessary.

After culturing, when the FZD10 protein or its partial peptide is produced within the microorganism or cell, the protein or its partial peptide is extracted by homogenizing the microorganism or cell. When the FZD10 protein or its partial peptide is secreted from the microorganism or cell, the culture medium is used as is, or debris of the microorganism or cell is removed from the culture medium, for example, by centrifugation. Thereafter, the FZD10 protein or its partial peptide can be isolated from the culture and purified by a conventional biochemical method for the isolation and purification of proteins, such as ammonium sulfate precipitation, gel chromatography, ion-exchange chromatography, and affinity chromatography, either individually or in combination.

Whether or not the FZD10 protein or its partial peptide has been obtained can be confirmed, for example, by SDS polyacrylamide gel electrophoresis.

Next, the obtained FZD10 protein or its partial peptide, or the transformant is dissolved in a buffer to prepare an immunogen. Where necessary, an adjuvant can be added thereto for effective immunization. Such adjuvants include, for example, commercially available Freund's complete adjuvant and Freund's incomplete adjuvant. Any of these adjuvants can be used alone or in combination.

The immunogen so prepared is administered to a mammal such as a rabbit, rat, or mouse. The immunization is performed mainly by intravenous, subcutaneous, or intraperitoneal injection. The interval of immunization is not specifically limited and the mammal is immunized one to 3 times at intervals ranging from several days to weeks. Antibody-producing cells are collected 1 to 7 days after the last immunization. Examples of the antibody-producing cells include spleen cells, lymph node cells, and peripheral blood cells.

To obtain a hybridoma, an antibody-producing cell and a myeloma cell are fused. As the myeloma cell to be fused with the antibody-producing cell, a generally available established cell line can be used. Preferably, the cell line used should have drug selectivity and properties such that it can not survive in a HAT selective medium (containing hypoxanthine, aminopterin, and thymidine) in unfused form and can survive only when fused with an antibody-producing cell. Possible myeloma cells include, for example, mouse myeloma cell lines such as P3X63-Ag.8.U1 (P3U1), and NS-I.

Next, the myeloma cell and the antibody-producing cell are fused. For the fusion, these cells are mixed, preferably at the ratio of the antibody-producing cell to the myeloma cell of 5:1, in a culture medium for animal cells which does not contain serum, such as DMEM and RPMI-1640 media, and fused in the presence of a cell fusion-promoting agent such as polyethylene glycol (PEG). The cell fusion may also be carried out by using a commercially available cell-fusing device using electroporation.

Then, the hybridoma is picked up from the cells after above fusion treatment. For example, a cell suspension is appropriately diluted with, for example, the RPMI-1640 medium containing fetal bovine serum and then plated onto a microtiter plate. A selective medium is added to each well, and the cells are cultured with appropriately replacing the selective medium. As a result, the cells that grow about 30 days after the start of culturing in the selective medium can be obtained as the hybridoma.

The culture supernatant of the growing hybridoma is then screened for the presence of an antibody that reacts with the FZD10 protein or its partial peptide. The screening of hybridoma can be performed according to a conventional procedure, for example, using enzyme-linked immunosorbent assay (ELISA), enzyme immunoassay (EIA) or radioimmunoassay (RIA). The fused cells are cloned by the limiting dilution to establish a hybridoma, which produces the monoclonal antibody of interest.

The monoclonal antibody can be collected from the established hybridoma, for example, by a conventional cell culture method or by producing the ascites. If necessary, the antibody can be purified in the above-described antibody collecting method according to a known procedure such as ammonium sulfate precipitation, ion-exchange chromatography, gel filtration, affinity chromatography, or a combination thereof.

The globulin type of the monoclonal antibodies useful in the present invention is not specifically limited, as long as they are capable of specifically binding to the FZD10 protein and can be any of IgG, IgM, IgA, IgE, and IgD. Among them, IgG and IgM are preferred.

In the present invention, murine monoclonal antibodies 93-22 and 92-13 are successfully established and preferably used. The hybridoma clone 93-22 producing mouse monoclonal antibody 93-22 was deposited by Shuichi Nakatsuru internationally at the IPOD International Patent Organism Depository of the National Institute of Advanced Industrial Science and Technology (AIST Tsukuba Central 6, 1-1, Higashi 1-chome, Tsukuba-shi, Ibaraki-Ken, 305-8566 Japan) as of Jun. 14, 2006 under the deposit number of FERM BP-10620. Also, hybridoma clone 92-13 producing mouse monoclonal antibody 92-13 was deposited by Shuichi Nakatsuru internationally at the IPOD International Patent Organism Depository of the National Institute of AIST as of Jun. 28, 2006 under the deposit number of FERM BP-10628. The monoclonal antibody produced by the hybridoma may be preferably used in the present invention.

In the present invention, a recombinant-type monoclonal antibody may also be used, which can be produced by cloning an antibody gene from the hybridoma, integrating the antibody gene into a suitable vector, introducing the vector into a host, and producing the antibody from the host according to a conventional genetic recombination technique (see, for example, Vandamme, A. M. et al., Eur. J. Biochem. (1990) 192, 767-75).

More specifically, mRNA encoding variable (V) region of the anti-FZD10 mouse monoclonal antibody is isolated from the antibody-producing hybridoma (for example, those described above). The isolation of the mRNA is performed by preparing a total RNA by any known method, such as guanidium ultracentrifugation method (Chirgwin, J. M. et al., Biochemistry (1979) 18, 5294-9) and AGPC method (Chomczynski, P. et al., Anal. Biochem. (1987) 162, 156-9), and then producing the desired mRNA from the total RNA using mRNA Purification Kit (Pharmacia) or the like. Alternatively, the mRNA may also be prepared directly using QuickPrep mRNA Purification Kit (Pharmacia).

Next, cDNA for the antibody V-region is synthesized from the mRNA with a reverse transcriptase. The synthesis of the cDNA may be performed using a commercially available kit, for example, Gene Racer™ Kit (lnvitrogen). The cDNA may also be synthesized or amplified by 5′-RACE method (Frohman, M. A. et al., Proc. Natl. Acad. Sci. USA (1988) 85, 8998-9002; Belyaysky, A. et al., Nucleic Acids Res. (1989) 17, 2919-32) using 5′-Ampli FINDER RACE Kit (Clontech) in combination with a PCR method.

The amino acid sequences of H chain and L chain of mouse monoclonal antibody 92-13 are shown in SEQ ID NO: 57 and 59, respectively (encoded by the nucleotide sequence as shown in SEQ ID NO: 58 and 60, respectively). The amino acid sequences of H chain and L chain of mouse monoclonal antibody 93-22 are shown in SEQ ID NO: 61 and 63, respectively (encoded by the nucleotide sequence as shown in SEQ ID NO: 62 and 64, respectively). Based on the sequence information, primers used for amplifying the H chain or L chain of mouse monoclonal antibody of interest can be designed using a conventional method.

A DNA fragment of interest is isolated and purified from the resultant PCR product and then ligated to a vector DNA to obtain a recombinant vector. The recombinant vector is introduced into a host such as E. coli, and a colony containing a desired recombinant vector is selected. The nucleotide sequence of the DNA of interest in the recombinant vector is confirmed using, for example, an automated sequencer.

Once DNA encoding the anti-FZD10 antibody V-region is obtained, the DNA is integrated into an expression vector containing DNA encoding the antibody constant (C) region.

For the production of the anti-FZD10 antibody used in the present invention, the antibody gene is integrated into an expression vector so that the antibody gene can be expressed under the control of expression control elements (e.g., enhancer, promoter). A host cell is transformed with the expression vector to express the antibody.

In the expression of the antibody gene, DNA encoding heavy (H) chain and DNA encoding light (L) chain of the antibody may be integrated into separate expression vectors, and then a host cell is co-transformed with the resultant recombinant expression vectors. Alternatively, both DNA encoding H-chain and DNA encoding L-chain of the antibody may be integrated together into a single expression vector, and then a host cell is transformed with the resultant recombinant expression vector (for example, WO 94/11523).

The antibody gene can be expressed by known methods. For the expression in a mammalian cell, a conventional useful promoter, the antibody gene to be expressed and a poly(A) signal (located downstream to the 3′ end of the antibody gene) may be operably linked. For example, as the useful promoter/enhancer system, a human cytomegalovirus immediate early promoter/enhancer system may be used.

Other promoter/enhancer systems, for example, those derived from viruses (e.g., retrovirus, polyoma virus, adenovirus and simian virus 40 (SV40)) and those derived from mammalian cells (e.g., human elongation factor 1 alpha (HEF1 alpha)), may also be used for the expression of the antibody in the present invention.

When SV40 promoter/enhancer system is used, the gene expression may be performed readily by the method of Mulligan et al. (Nature (1979) 277, 108-14.). When HEF1 alpha promoter/enhancer system is used, the gene expression may be performed readily by the method of Mizushima et al. (Nucleic Acids Res. (1990) 18, 5322.).

For the expression in E. coli, a conventional useful promoter, a signal sequence for secreting the antibody of interest and the antibody gene may be operably linked. As the promoter, lacZ promoter or araB promoter may be used. When lacZ promoter is used, the gene expression may be performed by the method of Ward et al. (Nature (1098) 341, 544-6.; FASBE J. (1992) 6, 2422-7.), while when araB promoter is used, the gene expression may be performed by the method of Better et al. (Science (1988) 240, 1041-3.).

With respect to the signal sequence for secretion of the antibody, when the antibody of interest is intended to be secreted in a periplasmic space of the E. coli, pelB signal sequence (Lei, S. P. et al., J. Bacteriol. (1987) 169, 4379-83.) may be used. The antibody secreted into the periplasmic space is isolated and then refolded so that the antibody takes an appropriate configuration.

The replication origin derived from viruses (e.g., SV40, polyoma virus, adenovirus, bovine papilloma virus (BPV)) or the like may be used. In order to increase the gene copy number in the host cell system, the expression vector may further contain a selective marker gene, such as an aminoglycoside phosphotranferase (APH) gene, a thymidine kinase (TK) gene, an E. coli xanthine-guanine phosphoribosyltransferase (Ecogpt) gene and a dihydrofolate reductase (dhfr) gene.

For the production of the antibody used in the present invention, any expression system including eukaryotic and prokaryotic cell systems may be used. The eukaryotic cell includes established cell lines of animals (e.g., mammals, insects, molds and fungi, yeast). The prokaryotic cell includes bacterial cells such as E. coli cells. It is preferable that the antibody used in the present invention be expressed in a mammalian cell, such as a CHO, COS, myeloma, BHK, Vero and HeLa cell.

Next, the transformed host cell is cultured in vitro or in vivo to produce the antibody of interest. The cultivation of the host cell may be performed by any known method. The culture medium that can be used herein may be DMEM, MEM, RPMI 1640 or IMDM medium. The culture medium may contain a serum supplement, such as fetal calf serum (FCS).

In the production of the recombinant antibody, besides the above-mentioned host cells, a transgenic animal may also be used as a host. For example, the antibody gene is inserted into a predetermined site of a gene encoding a protein inherently produced in the milk of an animal (e.g., beta-casein) to prepare a fusion gene. A DNA fragment containing the antibody gene-introduced fusion gene is injected into an embryo of a non-human animal, and the embryo is then introduced into a female animal. The female animal having the embryo therein bears a transgenic non-human animal. The antibody of interest is secreted in the milk from the transgenic non-human animal or a progeny thereof. For the purpose of increasing the amount of the antibody-containing milk, an appropriate hormone may be administered to the transgenic animal (Ebert, K. M. et al., Bio/Technology (1994) 12, 699-702.).

The antibody expressed and produced as described above may be isolated from the cells or the host animal body and purified. The isolation and purification of the antibody used in the present invention may be performed on an affinity column. Other methods conventionally used for the isolation and purification of an antibody may be also be used; thus the method is not particularly limited. For example, various chromatographies, filtration, ultrafiltration, salting out and dialysis may be used singly or in combination to isolate and purify the antibody of interest (Antibodies A Laboratory Manual. Ed. Harlow, David Lane, Cold Spring Harbor Laboratory, 1988).

(2) Chimeric Antibody and Humanized Antibody

In the present invention, an artificially modified recombinant antibody may be used, including a chimeric antibody and a humanized antibody. These modified antibodies can be prepared by any known method. For example, techniques developed for the production of “chimeric antibodies” (Morrison et al., 1984, Proc. Natl. Acad. Sci., 81: 6851-5.; Neuberger et al., 1984, Nature, 312: 604-8.; Takeda et al., 1985, Nature, 314: 452-4.) can be used. A chimeric antibody is a molecule in which different portions are derived from different animal species, such as those having a variable region derived from a murine mAb and a human immunoglobulin constant region, e.g., “humanized antibodies”.

A chimeric antibody according to the present invention can be prepared by ligating the DNA encoding the antibody V-region to DNA encoding a human antibody C-region, integrating the ligation product into an expression vector, and introducing the resultant recombinant expression vector into a host to produce the chimeric antibody.

A humanized antibody is also referred to as “reshaped human antibody”, in which the complementarity determining regions (CDRs) of an antibody of a non-human mammal (e.g., a mouse) are grafted to those of a human antibody. The general genetic recombination procedure for producing such humanized antibody is also known (for example, EP 125023; WO 96/02576.).

Specifically, a DNA sequence in which mouse antibody CDRs are ligated through framework regions (FRs) is designed, and synthesized by a PCR method using several oligonucleotides as primers which were designed to have regions overlapping to the terminal regions of the CDRs and the FRs. The resultant DNA is ligated to DNA encoding the human antibody C-region, and the ligation product is integrated into an expression vector. The resultant recombinant expression vector is introduced into a host, thereby producing the humanized antibody (for example, WO 96/02576).

The FRs ligated through the CDRs are selected so that the CDRs can form a functional antigen binding site. If necessary, an amino acid(s) in the FRs of the antibody V-region may be replaced so that the CDRs of the reshaped human antibody can form an appropriate antigen binding site (Sato, K. et al., Cancer Res. (1993) 53, 851-6.).

The chimeric antibody is composed of V-regions derived from a non-human mammal antibody and C-regions derived from a human antibody. The humanized antibody is composed of CDRs derived from a non-human mammal antibody and FRs and C-regions derived from a human antibody. The humanized antibody may be useful for clinical use, because the antigenicity of the antibody against a human body is reduced.

A specific example of a chimeric antibody or a humanized antibody used in the present invention is an antibody in which the CDRs are derived from the mouse monoclonal antibody 92-13 or an antibody in which the CDRs are derived from the mouse monoclonal antibody 93-22. The method for producing such chimeric antibodies and humanized antibodies are described below.

To clone DNA comprising a nucleotide sequence coding for V region of the anti-FZD10 mouse monoclonal antibody, mRNA can be isolated from hybridomas and each cDNA in the V regions of L and H chains can be synthesized with the use of a reverse transcriptase as described above. In the synthesis of cDNA, Oligo-dT primer or other appropriate primer which hybridizes to L or H chain C region may be used. For example, but not limited to, CHI (IgG2a) primer having the nucleotide sequence as shown in SEQ ID NO: 3 for H chain V region and CL1 (kappa) primer having the nucleotide sequence as shown in SEQ ID NO: 4 for L chain V region can be used.

Amplification of cDNA of both L and H chains can be performed by PCR (polymerase chain reaction) using a commercially available kit (for example, GeneRacer™ kit from Invitrogen) or using a known method including 5′-RACE method (Frohman, M. A. et al., Proc. Natl. Acad. Sci. USA, 85, 8998-9002, 1988.; Belyaysky, A. et al., Nucleic Acids Res., 17, 2919-32, 1989.).

The specific primers for amplifying DNA for V regions of the mouse monoclonal antibody 92-13 include primers having the nucleotide sequences shown in SEQ ID NOs: 5 and 6 for H chain V region and primers having the nucleotide sequences shown in SEQ ID NOs: 7 and 8 for L chain V region. Using these primers, a DNA encoding H chain V region having an amino acid sequence as shown in SEQ ID NO: 13 and a DNA encoding L chain V region having an amino acid sequence as shown in SEQ ID NO: 21 can be amplified. The specific primers for amplifying DNA for V regions of the mouse monoclonal antibody 93-22 include primers having the nucleotide sequences shown in SEQ ID NOs: 53 and 54 for H chain V region and primers having the nucleotide sequences shown in SEQ ID NOs: 55 and 56 for L chain V region. Using these primers, a DNA encoding H chain V region having an amino acid sequence as shown in SEQ ID NO: 29 and a DNA encoding L chain V region having an amino acid sequence as shown in SEQ ID NO: 37 can be amplified.

Then, the amplified products are subjected to agarose gel electrophoresis according to conventional procedures, and DNA fragments of interest are excised, recovered, purified and ligated to a vector DNA.

The obtained DNA and vector DNA can be ligated using a known ligation kit to construct a recombinant vector. A vector DNA may be prepared in a known method: J. Sambrook, et al., “Molecular Cloning”, Cold Spring Harbor Laboratory Press, 1989. The vector DNA is digested with restriction enzyme(s), and the nucleotide sequence of a desired DNA can be determined by a known method or using an automated sequencer.

Once DNA fragments coding for L and H chain V regions of mouse monoclonal antibody (hereinafter L or H chain of an antibody may sometimes be referred to as “mouse L or H chain” for mouse antibodies and “human L or H chain” for human antibodies) are cloned, the DNAs coding for mouse V regions and DNAs coding for human antibody constant regions are ligated and expressed to yield chimeric antibodies.

A standard method for preparing chimeric antibodies involves ligating a mouse leader sequence and V region sequence present in a cloned cDNA to a sequence coding for a human antibody C region already present in an expression vector of a mammalian cell. Alternatively, a mouse leader sequence and V region sequence present in a cloned cDNA are ligated to a sequence coding for a human antibody C region followed by ligation to a mammalian cell expression vector.

The polypeptide comprising human antibody C region can be any of H or L chain C regions of human antibodies, including, for example, C gamma 1, C gamma 2, C gamma 3 or C gamma 4 for human H chains or C lambda or C kappa for L chains.

To prepare a chimeric antibody, two expression vectors are first constructed; that is, an expression vector containing DNAs coding for mouse L chain V region and human L chain C region under the control of an expression control element such as an enhancer/promoter system, and an expression vector containing DNAs coding for mouse H chain V region and human H chain C region under the control of an expression control element such as an enhancer/promoter system, are constructed. Then, host cells such as mammalian cells (for example, COS cell) are cotransformed with these expression vectors and the transformed cells are cultivated in vitro or in vivo to produce a chimeric antibody: see, for example, WO91/16928.

Alternatively, the mouse leader sequence present in the cloned cDNA and DNAs coding for mouse L chain V region and human L chain C region as well as the mouse leader sequence and DNAs coding for mouse H chain V region and human H chain C region are introduced into a single expression vector (see, for example, WO94/11523) and said vector is used to transform a host cell; then, the transformed host is cultured in vivo or in vitro to produce a desired chimeric antibody.

The vector for the expression of H chain of a chimeric antibody can be obtained by introducing cDNA comprising a nucleotide sequence coding for mouse H chain V region (hereinafter referred to also as “cDNA for H chain V region”) into a suitable expression vector containing the genomic DNA comprising a nucleotide sequence coding for H chain C region of human antibody (hereinafter referred to also as “genomic DNA for H chain C region”) or cDNA coding for said region (hereinafter referred to also as “cDNA for H chain C region”). The H chain C region includes, for example, C gamma 1, C gamma 2, C gamma 3 or C gamma 4 regions.

The expression vectors having the genomic DNA coding for H chain C region, in particular, those coding for C gamma 1 region, include, for example, HEF-PMh-g gamma 1 (WO92/19759) and DHER-INCREMENT E-RVh-PM1-f (WO92/19759). Alternatively, human constant region library can be prepared using cDNA from human PBMC (peripheral blood mononuclear cells) as described previously (Liu, A. Y. et al., Proc. Natl. Acad. Sci. USA, Vol.84, 3439-43, 1987; Reff, M. E. et al., Blood, Vol. 83, No. 2, 435-45, 1994).

When cDNA coding for mouse H chain V region is inserted into these expression vectors, an appropriate nucleotide sequence can be introduced into said cDNA through PCR method. For instance, PCR may be effected using a PCR primer which is designed such that said cDNA has a recognition sequence for a suitable restriction enzyme at its 5′-end and Kozak consensus sequence immediately before the initiation codon thereof so as to improve the transcription efficiency, as well as a PCR primer which is designed such that said cDNA has a recognition sequence for a suitable restriction enzyme at its 3′-end and a splice donor site for properly splicing the primary transcription products of the genomic DNA to give a mRNA, to introduce these appropriate nucleotide sequences into the expression vector.

The thus constructed cDNA coding for mouse H chain V region is treated with a suitable restriction enzyme(s), then it is inserted into said expression vector to construct a chimeric H chain expression vector containing the genome DNA coding for H chain C region (C gamma 1 region).

The thus constructed cDNA coding for mouse H chain V region is treated with a suitable restriction enzyme(s), ligated to cDNA coding for said H chain C region C gamma 1, and inserted into an expression vector such as pQCXIH (Clontech) to construct an expression vector containing the cDNA coding for a chimeric H chain.

The vector for the expression of L chain of a chimeric antibody can be obtained by ligating a cDNA coding for mouse L chain V region and a genomic DNA or cDNA coding for L chain C region of a human antibody and introducing into a suitable expression vector. The L chain C region includes, for example, kappa chain and lambda chain.

When an expression vector containing cDNA coding for mouse L chain V region is constructed, appropriate nucleotide sequences such as a recognition sequence or Kozak consensus sequence can be introduced-into said expression vector through PCR method.

The entire nucleotide sequence of cDNA coding for human L lambda chain C region may be synthesized by a DNA synthesizer and constructed through PCR method. The human L lambda chain C region is known to have at least 4 different isotypes and each isotype can be used to construct an expression vector.

The constructed cDNA coding for human L lambda chain C region and the above constructed cDNA coding for mouse L chain V region can be ligated between suitable restriction enzyme sites and inserted into an expression vector such as pQCXIH (Clontech), to construct an expression vector containing cDNA coding for a L lambda chain of a chimeric antibody.

The DNA coding for human L kappa chain C region to be ligated to the DNA coding for mouse L chain V region can be constructed from, for example, HEF-PM1k-gk containing the genomic DNA (see WO92/19759). Alternatively, human constant region library can be prepared using cDNA from human PBMC (peripheral blood mononuclear cells) as described previously (Liu, A. Y. et al., Proc. Natl. Acad. Sci. USA, Vol. 84, 3439-43, 1987; Reff, M. E. et al., Blood, Vol. 83, No. 2, 435-45, 1994).

Recognition sequences for suitable restriction enzymes can be introduced, through PCR method, into 5′- and 3′-ends of DNA coding for L kappa chain C region, and the DNA coding for mouse L chain V region as constructed above and the DNA coding for L kappa chain C region can be ligated to each other and inserted into an expression vector such as pQCXIH (Clontech) to construct an expression vector containing cDNA coding for L kappa chain of a chimeric antibody.

In order to make a humanized antibody in which CDR of a mouse monoclonal antibody is grafted to a human antibody, it is desirable that there exists a high homology between FR of the mouse monoclonal antibody and FR of the human antibody. Accordingly, a comparison is made between V regions of H and L chains of mouse anti-FZD10 monoclonal antibody and the V regions of all the known antibodies whose structures have been elucidated with the use of Protein Data Bank. Further, they are simultaneously compared with the human antibody subgroups (HSG: Human subgroup) classified by Kabat et al. based on the length of antibody FR, the homology of amino acids, and the like: Kabat, E. A. et al, US Dep, Health and Human Services, US Government Printing Offices, 1991.

The first step for designing DNA coding for a humanized antibody V region is to select a human antibody V region as a basis for the designing. For example, FR of a human antibody V region having a homology of higher than 80% with FR of a mouse antibody V region can be used in the production of a humanized antibody.

In the humanized antibody, the C region and the framework (FR) regions of the V region of said antibody are originated from human and the complementarity determining regions (CDR) of the V region are originated from mouse. A polypeptide comprising the V region of the humanized antibody can be produced in the manner called CDR-grafting by PCR method so long as a DNA fragment of a human antibody would be available as a template. The “CDR-grafting” refers to a method wherein a DNA fragment coding for a mouse-derived CDR is made and replaced for the CDR of a human antibody as a template.

If a DNA fragment of a human antibody to be used as a template is not available, a nucleotide sequence registered in a database may be synthesized in a DNA synthesizer and a DNA for a V region of a humanized antibody can be produced by the PCR method. Further, when only an amino acid sequence is registered in the database, the entire nucleotide sequence may be deduced from the amino acid sequence on the basis of knowledge on the codon usage in antibodies as reported by Kabat, E. A. et al. in US Dep. Health and Human Services, US Government Printing Offices, 1991. This nucleotide sequence is synthesized in a DNA synthesizer and a DNA of a humanized antibody V region can be prepared by PCR method and introduced into a suitable host followed by expression thereof to produce the desired polypeptide.

General procedures of CDR-grafting by PCR method are described below when a DNA fragment of a human antibody as a template is available.

First, mouse derived DNA fragments corresponding to respective CDRs are synthesized. CDRs 1 to 3 are synthesized on the basis of the nucleotide sequences of the previously cloned mouse H and L chain V regions. For example, when a humanized antibody is produced based on the mouse monoclonal antibody 92-13, CDR sequences of chain V region can be the amino acid sequences as shown in SEQ ID NOs: 15 (VH CDRI), 17 (VH CDR2) and 19 (VH CDR3); and CDR sequences of L chain V region can be the amino acid sequences as shown in SEQ ID NOs: 23 (VL CDR1), 25 (VL CDR2) and 27 (VL CDR3). When a humanized antibody is produced based on the mouse monoclonal antibody 93-22, CDR sequences of H chain V region can be the amino acid sequences as shown in SEQ ID NOs: 31 (VH CDR1), 33 (VH CDR2) and 35 (VH CDR3); and CDR sequences of L chain V region can be the amino acid sequences as shown in SEQ ID NOs: 39 (VL CDR1), 41 (VL CDR2) and 43 (VL CDR3).

The DNA for H chain V region of a humanized antibody may be ligated to DNA for any human antibody H chain C region, for example, human H chain C gamma 1 region. As mentioned above, the DNA for H chain V region may be treated with a suitable restriction enzyme and ligated to a DNA coding for a human H chain C region under an expression control element such as an enhancer/promoter system to make an expression vector containing DNAs for a humanized H chain V region and a human H chain C region.

The DNA for L chain V region of a humanized antibody may be ligated to DNA for any human antibody L chain C region, for example, human L chain C lambda region. The DNA for L chain V region may be treated with a suitable restriction enzyme and ligated to a DNA coding for a human L lambda chain C region under an expression control element such as an enhancer/promoter system to make an expression vector containing DNAs coding for a humanized L chain V region and a human L lambda chain C region.

The DNA coding for H chain V region of a humanized antibody and a human H chain C region and the DNA coding for a humanized L chain V region and human L chain C region may also be introduced into a single expression vector such as that disclosed in WO94/11523, said vector may be used to transform a host cell, and the transformed host may be cultivated in vivo or in vitro to produce a desired humanized antibody.

To produce a chimeric or humanized antibody, two expression vectors as above mentioned should be prepared. Thus, with respect to a chimeric antibody, an expression vector comprising a DNA coding for a mouse H chain V region and a human H chain C region under the control of an expression control element such as an enhancer/promoter, and an expression vector comprising a DNA coding for a mouse L chain V region and a human L chain C region under the control of an expression control element are constructed. With respect to a humanized antibody, an expression vector comprising a DNA coding for a humanized H chain V region and a human H chain C region under the control of an expression control element, and an expression vector comprising a DNA coding for a humanized L chain V region and a human L chain C region under the control of an expression control element are constructed.

Then, a host cell such as a mammalian cell (for example, COS cell) may be cotransformed with these expression vectors and the resulting transformed cell may be cultured in vitro or in vivo to produce the chimeric or humanized antibody (see, for example, WO91/16928).

Alternatively, a DNA coding for H chain V and C regions and a DNA coding for L chain V and C regions may be ligated to a single vector and transformed into a suitable host cell to produce an antibody. Thus, in the expression of a chimeric antibody, a DNA coding for a mouse leader sequence present in the cloned cDNA, a mouse H chain V region and a human H chain C region as well as a DNA coding for a mouse leader sequence, a mouse L chain V region and a human L chain C region, can be introduced into a single expression vector such as one disclosed in e.g. WO94/11523. In the expression of a humanized antibody, a DNA coding for a humanized H chain V region and a human H chain C region and a DNA coding for a humanized L chain V region and a human L chain C region may be introduced into a single expression vector such as one disclosed in e.g. WO94/11523. Such a vector is used to transform a host cell and the transformed host is cultured in vivo or in vitro to produce a chimeric or humanized antibody of interest.

Any expression system may be used to produce the chimeric or humanized antibody against FZD10 protein according to the present invention. For example, eukaryotic cells include animal cells such as established mammalian cell lines, fungal cells, and yeast cells; prokaryotic cells include bacterial cells such as Escherichia coli. Preferably, the chimeric or humanized antibody of the present invention is expressed in a mammalian cell such as COS or CHO cell.

Any conventional promoters useful for the expression in mammalian cells may be used. For example, human cytomegalovirus (HCMV) immediate early promoter is preferably used. In addition, promoters for gene expression in mammalian cells may include virus promoters, such as those of retrovirus, polyoma virus, adenovirus and simian virus (SV) 40, and mammalian cell derived promoters, such as those of human polypeptide chain elongation factor-1 alpha (HEF-1 alpha). For example, SV40 promoter may be readily used according to Mulligan et al. method (Nature, 277, 108-14, 1979); Mizushima, S. et al. method (Nucleic Acids Research, 18, 5322, 1990) may be easily used with HEF-1 alpha promoter.

Replication origin includes those derived from SV40, polyoma virus, adenovirus or bovine papilloma virus (BPV). Further, the expression vector may comprise a gene for phosphotransferase APH(3′) II or I (neo), thymidine kinase (TK), E. coli xanthine-guanine phosphoribosyltransferase (Ecogpt) or dihydrofolate reductase (DHFR) as a selective marker for increasing the gene copy number in a host cell system.

The chimeric or humanized antibody of interest which is thus produced by culturing the transformant transformed with a DNA coding for the chimeric or humanized antibody may be isolated from the cell and then purified.

The isolation and purification of the chimeric or humanized antibody of interest may be carried out by using a protein A agarose column, but may also be performed by any methods used in isolation and purification of a protein and thus is not limited. For instance, a chromatography, ultrafiltration, salting out and dialysis may optionally be selected or combined to isolate and purify the chimeric or humanized antibody.

After isolating the chimeric antibody or humanized antibody, the concentration of the resulting purified antibody can be determined by ELISA.

The determination of the antigen-binding activity or other activities including binding activity to a normal cell of the chimeric antibody or humanized antibody may be performed by any known methods (Antibodies A Laboratory Manual, Ed. Harlow, David Lane, Cold Spring Harbor Laboratory, 1988).

As the method for the determination of the antigen-binding activity of an antibody, techniques such as ELISA (enzyme-linked immunosorbent assay), EIA (enzyme immunoassay), RIA (radioimmunoassay) or fluorescent assay may be employed.

(3) Antibody Fragment and Modified Antibody

The antibody used in the present invention may be any fragment thereof or a modified antibody, as long as it can bind to FZD10 protein and inhibit its activity. For example, the fragment of the antibody includes Fab, F(ab′)₂, Fv, or a single chain Fv (scFv) composed of a H-chain Fv fragment or a L-chain Fv fragment linked together through a suitable linker. Specifically, such antibody fragments can be produced by cleaving the antibody with an enzyme (e.g., papain, pepsin) into antibody fragments, or by constructing a gene encoding the antibody fragment and inserting the gene into an expression vector and introducing the resultant recombinant expression vector into a suitable host cell, thereby expressing the antibody fragment (see, for example, Co, M. S., et al., J. Immunol. (1994), 152, 2968-76; Better, M. & Horwitz, A. H., Methods in Enzymology (1989), 178, 476-96, Academic Press, Inc.; Pluckthun, A. & Skerra, A., Methods in Enzymology (1989) 178, 497-515, Academic Press, Inc.; Lamoyi, E., Methods in Enzymology (1989) 121, 652-63; Rousseaux, J. et al., Methods in Enzymology (1989) 121, 663-9; and Bird, R. E. et al., Trends Biotechnol. (1991) 9, 132-7). Alternatively, Fab expression libraries may be constructed (Huse et al., 1989, Science, 246: 1275-81) to allow rapid and easy identification of monoclonal Fab fragments with the desired specificity.

A scFv can be produced by ligating the H-chain V-region to the L-chain V-region through a linker, preferably a peptide linker (Huston, J. S. et al., Proc. Natl. Acad. Sci. USA (1988) 85, 5879-83). The H-chain V-region and the L-chain V-region in the scFv may be derived from any one of the antibodies described herein. The peptide linker which binds the V-regions may be any single chain peptide, for example, of 12-19 amino acid residues.

As a modified antibody, for example, anti-FZD10 antibody or fragment thereof conjugated to any molecule (e.g., polyethylene glycol) may also be used. Such modified antibodies are also encompassed in the “antibody” of the present invention. The modified antibodies can be prepared by chemical modifications of the antibodies. The chemical modification techniques suitable for this purpose have already been established in the art.

2. Therapeutic Uses

Described below are methods and pharmaceutical compositions for treating and/or preventing FZD10-associated disease using the antibody of the present invention. The outcome of a treatment is to at least produce in a treated subject a healthful benefit, which in the case of tumors, includes but is not limited to remission of the tumors, palliation of the symptoms of the tumors, and control of metastatic spread of the tumors.

Specifically, the method for treating and/or preventing FZD10-associated disease in a subject according to the present invention comprises administering to a subject in need thereof the antibody or the fragment described above.

The term “subject” herein refers to a subject who has suffered from FZD10-associated disease and also a subject suspected to have FZD10-associated disease. The subject in the present invention may be animals including mammals and avian animals. For example, mammals may include humans, mice, rats, monkeys, rabbits, and dogs.

The term “FZD10-associated disease” herein refers to a disease associated with the over-expression of FZD10 protein. Specifically, FZD10-associated diseases include, but are not limited to, synovial sarcoma (SS), colorectal cancer, gastric cancer, chronic myeloid leukemia (CML), and acute myeloid leukemia (AML).

The antibody or fragment thereof described herein can specifically bind to FZD10 protein, so when the antibody or fragment thereof is administered to a subject, it binds to FZD10 protein in the subject and the activity of FZD10 protein may be inhibited. Alternatively, when the antibody or fragment thereof may be conjugated with a therapeutic moiety and administered to a subject, it is derivered to a region that expresses FZD10 protein (i.e. suffered region) in a subject and the therapeutic moiety can be selectively delivered to the suffered region and acted thereon. Such therapeutic moiety may be any therapeutics that are known or will be developed for having a therapeutic efficacy on FZD10-associated disease and includes, but not limited to, a radioisotope label and chemotherapeutic agent. A radioisotope label which can be used as therapeutics can be selected depending on a variety of elements including β-ray energy and its emission efficiency, the presence or absence of γ-ray emitted, its energy and emission efficiency, physical half-life, and labeling procedure. Generally, the radioisotope label based on yttrium (such as ⁹⁰Y) and iodine (such as ¹²⁵I and ¹³¹I) may be used. A chemotherapeutic agent may be any agent that is known or will be developed for treating FZD10-associated disease and includes, but not limited to, methotrexate, taxol, mercaptopurine, thioguanine, cisplatin, carboplatin, mitomycin, bleomycin, doxorubicin, idarubicin, daunorubicin, dactinomycin, vinblastine, vincristine, vinorelbine, paclitaxel, and docetaxel. The antibody or fragment thereof described herein can selectively bind to FZD10 protein and not bind to a normal cell, so side effect which is caused by the antibody or fragment thereof, or radioisotope or chemotherapeutic agent can be effectively avoided and therefore the therapeutic potency may be high.

The antibody or fragment thereof described herein can be administered to a subject at effective doses to treat or prevent the FZD10-associated disease. An effective dose refers to that amount of an antibody or a fragment thereof sufficient to result in a healthful benefit in the treated subject. Formulations and methods of administration that can be employed when the pharmaceutical composition contains an antibody of the present invention are described below.

Pharmaceutical compositions for use in accordance with the present invention can be formulated in conventional manner using one or more pharmaceutically acceptable carriers or excipients.

The antibodies or fragments thereof can be formulated for parenteral administration e., intravenous or intramuscular) by injection, via, for example, bolus injection or continuous infusion. Formulations for injection can be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions can take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the antibody can be in lyophilized powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.

Toxicity and therapeutic efficacy of the antibody or fragment, or the therapeutic moiety conjugated thereto can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., for determining the LD50 (the dose lethal to 50% of the population) and the ED50 (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index and it can be expressed as the ratio LD/ED.

Antibodies or therapeutic moieties that exhibit large therapeutic indices are preferred. While antibodies or moieties that exhibit toxic side effects can be used, care should be taken to design a delivery system that targets such antibodies or moieties to the site of affected tissue in order to minimize potential damage to uninfected cells and, thereby, reduce side effects.

The data obtained from the cell culture assays and animal studies can be used in formulating a range of dosages for use in humans. The dosage of such antibodies lies preferably within a range of circulating plasma concentrations that include the ED50 with little or no toxicity. The dosage can vary within this range depending upon the dosage form employed, the route of administration utilized and types and amounts of the therapeutic moiety conjugated. For any antibody used in the method of the invention, the effective dose can be estimated initially from cell culture assays. A dose can be formulated in animal models to achieve a circulating plasma concentration range that includes the IC50 (i.e., the concentration of the test antibody that achieves a half-maximal inhibition of symptoms) as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Levels in plasma can be measured, for example, by high performance liquid chromatography.

While depending on the conditions and age of the subject and/or administration route, one skilled in the art can select an appropriate dose of the pharmaceutical composition of the present invention. For example, the pharmaceutical composition of the present invention is administered in an amount such that the antibody according to the present invention is administered to the subject in a day in an amount of about 3 to about 15 μg per kg body weight of subject, and preferably of about 10 to about 15 μg per kg body weight of subject. The administration interval and times can be selected in consideration of the condition and age of the subject, administration route, and response to the pharmaceutical composition. For example, the pharmaceutical composition can be administered to the subject one to 5 times, preferably 1 times a day for 5 to 10 days.

The pharmaceutical composition can be administered systemically or locally. It is preferably administered in a targeting delivery manner so as to deliver the active component to an affected site.

In particular embodiments, the methods and compositions of the present invention are used for the treatment or prevention of FZD10-associated disease together with one or a combination of chemotherapeutic agents including, but not limited to, methotrexate, taxol, mercaptopurine, thioguanine, cisplatin, carboplatin, mitomycin, bleomycin, doxorubicin, idarubicin, daunorubicin, dactinomycin, vinblastine, vincristine, vinorelbine, paclitaxel, and docetaxel.

With respect to radiation therapy, any radiation therapy protocol can be used depending upon the type of FZD10-associated disease to be treated. For example, but not by way of limitation, X-ray radiation can be administered. Gamma ray emitting radioisotopes, such as radioactive isotopes of radium, cobalt, and other elements may also be administered to expose tissues.

In another embodiment, chemotherapy or radiation therapy is administered, preferably at least an hour, five hours, 12 hours, a day, a week, a month, and more preferably several months (e.g., up to three months) subsequent to using the methods and compositions containing the antibody of the present invention. The chemotherapy or radiation therapy administered prior to, concurrently with, or subsequent to the treatment using the methods and compositions according to the present invention can be administered by any method known in the art.

3. Diagnostic and Prognotic Uses

Antibodies directed against FZD10 protein or fragments thereof may also be used as diagnostics and prognostics, as described herein. Such diagnostics methods may used to detect the presence or absence of FZD10-associated disease and the risk of having the disease. The method for diagnosis and/or prognosis of an FZD10-associated disease of the present invention comprises immunologically detecting or determining the FZD10 protein derived from the disease in a sample using an antibody or a fragment thereof according to the present invention. Specifically, a method for diagnosis or prognosis of FZD10-associated disease or of a predisposition to develop the disease in a subject according to the present invention comprises:

(a) contacting a sample from the subject with an antibody against FZD10 protein or a fragment thereof;

(b) detecting the FZD10 protein in the sample; and

(c) judging whether or not the subject suffers from or is at risk of developing the disease based on the relative abundance of the FZD10 protein compared to a control.

The method for diagnosis and/or prognosis of the present invention can be performed based on any procedures, as long as it is an assay using an antibody, i.e., an immunological assay. Thereby one can detect the FZD10 protein using the antibody or a fragment thereof of the present invention as the antibody used in the assay. For example, the FZD10 protein can be detected by using an immunohistochemical staining, immunoassay such as enzyme immunoassays (ELISA and EIA), immunofluorescent assay, radioimmunoassay (RIA), or Western blotting.

A sample to be tested in the method for diagnosis and/or prognosis of FZD10-associated disease of the present invention is not specifically limited, as long as it is a biological sample that may contain the FZD10 protein derived from the FZD10-associated disease. Examples of the sample include extract of a cell or organ, and tissue sections, as well as blood, sera, plasma, lymphocyte cultivated supernatant, urine, spinal fluid, saliva, sweat, and ascites. The abundance of the FZD10 protein as determined in samples such as tumor tissue, tumor biopsy, and metastasis tissue by using the antibody or a fragment thereof of the present invention is specifically useful as an index of an FZD10-associated disease.

For example, antibodies and fragments thereof described herein may be used to quantitatively or qualitatively detect the FZD10 protein. The antibodies (or fragment thereof) of the present invention may, additionally, be employed histologically, as in immunofluorescence or immunoelectron microscopy, for in situ detection of FZD10 protein. In situ detection may be accomplished by removing a histological sample from a subject, such as paraffin-embedded sections of tissues (such as surgical specimens) and applying thereto a labeled antibody of the present invention. The antibody (or fragment thereof) is preferably applied by overlaying a sample with the labeled antibody (or fragment thereof). Using the present invention, those skilled in the art will readily perceive that any of a wide variety of histological methods (such as staining procedures) can be modified in order to achieve such in situ detection.

Immunoassays for FZD10 protein will typically comprise incubating a sample from a subject to be examined, such as a biological fluid, a tissue extract, freshly harvested cells, or lysates of cells that have been incubated in cell culture, in the presence of a detectably labeled antibody of the present invention, and detecting the bound antibody by any of a number of techniques well-known in the art.

The sample may be brought into contact with and immobilized onto a solid phase support or carrier such as nitrocellulose, or another solid support which is capable of immobilizing cells, cell particles, or soluble proteins. The support may then be washed with suitable buffers followed by treatment with the detectably labeled antibody against FZD10. The solid phase support may then be washed with the buffer a second time to remove unbound antibody. The amount of bound label on the solid support may then be detected by conventional means.

The term “solid phase support or carrier” means any support capable of binding an antigen or an antibody. Those skilled in the art will know many suitable carriers for binding antibodies or antigens, or will be able to ascertain the same by use of routine experimentation.

The binding activity of a given lot of anti-FZD10 antibody may be determined according to well-known methods. Those skilled in the art will be able to determine operative and optimal assay conditions for each determination by employing routine experimentation.

To detect a reaction between the antibody (or its fragment) of the present invention and the FZD10 protein derived from an FZD10-associated disease affected site in a sample easily, the reaction can be directly detected by labeling the antibody of the present invention or indirectly detected by using a labeled secondary antibody. The latter indirect detection procedure, such as a sandwich assay or competitive assay of ELISA, is preferably used in the method of the present invention for better sensitivity.

Examples of labels for use herein are as follows. Peroxidases (PODs), alkaline phosphatases, β-galactosidase, urease, catalase, glucose oxidase, lactate dehydrogenase, amylases, and biotin-avidin complexes can be used in an enzyme immunoassay. Fluorescein isothiocyanate (FITC), tetramethylrhodamine isothiocyanate (TRITC), substituted rhodamine isothiocyanate, dichlorotriazine isothiocyanate and Alexa488 can be used in an immunofluorescent assay. Tritium, iodine (such as ¹²⁵I, and ¹³¹I), and indium (such as ¹¹¹In) can be used in a radioimmunoassay. NADH-FMNH₂-luciferase assay, luminol-hydrogen peroxide-POD system, acridinium esters, and dioxetane compounds can be used in an immunoluminescent assay.

The label can be attached to the antibody according to a conventional procedure. For example, the label can be attached to the antibody by a glutaraldehyde method, maleimide method, pyridyl disulfide method, or periodate method in the enzyme immunoassay, and by a chloramine T method or Bolton-Hunter method in the radioimmunoassay.

The assay can be performed according to a known procedure (Ausubel, F. M. et al. Eds., Short Protocols in Molecular Biology, Chapter 11 “Immunology” John Wiley & Sons, Inc. 1995).

For example, when the antibody of the present invention is directly labeled with the label described above, the sample is brought into contact with the labeled antibody to thereby form a complex between the FZD10 protein and the antibody. Then, unbound labeled antibody is separated, and the level of the FZD10 protein in the sample can be determined based on the amount of the bound labeled antibody or that of the unbound labeled antibody.

When a labeled secondary antibody is used, the antibody of the present invention is allowed to react with the sample in a primary reaction, and the resulting complex is allowed to react with the labeled secondary antibody in a secondary reaction. The primary reaction and the secondary reaction can be performed in reverse order, concurrently with some interval of time therebetween. The primary and secondary reactions yield a complex of [FZD10 protein]—[the antibody of the invention]—[the labeled secondary antibody] or a complex of [the antibody of the invention]—[FZD10 protein]—[the labeled secondary antibody]. Unbound labeled secondary antibody is then separated, and the level of the FZD10 protein in the sample can be determined based on the abundance of the bound labeled secondary antibody or that of the unbound labeled secondary antibody.

According to another embodiment, the antibody of the present invention is labeled with a radioisotope or a fluorescent label, and the labeled antibody is parenterally administered to a subject. Thus, the localization of a primary tumor and the related metastasized tumor of FZD10-associated disease can be rapidly found in a non-invasive manner. Such a diagnosis method is known as tumor in vivo imaging, and one skilled in the art can easily understand the procedures thereof. The labeled antibody can be administered to the subject systemically or locally, preferably through a parenteral route such as intravenous injection, intramuscular injection, intraperitoneal injection, or subcutaneous injection.

The antibodies according to the present invention specifically react with a FZD10 protein as mentioned above and can thereby be used in kits for diagnosis and/or prognosis of an FZD10-associated disease.

The kit for diagnosis and/or prognosis of the present invention comprises an antibody or a fragment thereof described herein. By detecting the FZD10 protein in a sample from a subject who is suspected to suffer from an FZD10-associated disease with the use of the kit for diagnosis and/or prognosis of the present invention, whether or not the subject suffers from the FZD10-associated disease can be rapidly and easily ascertained. Kits for diagnosis and/or prognosis of diseases using such immunological reactions have been widely known, and one skilled in the art can easily select appropriate components other than the antibody. The kits for diagnosis and/or prognosis of the present invention can be used in any means, as long as it is a means for immunoassay.

Examples

The present invention will be further illustrated by the following non-limiting examples.

Cell lines and tissue specimens used in the following examples were prepared as described below. Specifically, cell lines derived from synovial sarcomas (HS-SY-2, YaFuSS, 1973/99, Fuji and SYO-1), colon cancers (LoVo, SNU-C4 and SNU-C5), HEK293 and COS7 cells were grown in monolayers in appropriate media supplemented with 10% fetal bovine serum and 1% antibiotic/antimycotic solution, and maintained at 37° C. in air containing 5% CO₂. Primary synovial sarcoma (SS) samples were obtained after informed consent, and snap-frozen in liquid nitrogen immediately after resection and stored at −80° C.

Example 1 Generation of anti-FZD10 Monoclonal Antibodies

(1) Generating Monoclonal Antibodies with Cell Immunization

Mouse anti-FZD10 monoclonal antibodies (Mabs) were generated by immunizing four weeks old female Balb/c mice in their foot pads with 2×10⁷ COS-7 cells transfected with 2×10⁷ of pCAGGS/neo-FZD10-myc/His (Medical and Biological Laboratories, Nagoya, Japan). Construction of pCAGGS/neo-FZD10-myc/H is was reported previously (Nagayama, S., et al. (2005). Oncogene, 24, 6201-12.) and this expresses the entire coding sequence of FZD10 cDNA and Myc and His epitope tags at its C terminus. The mice had been immunized with Freund complete adjuvant (Mitsubishi Kagaku latron, Inc., Tokyo, Japan) in one day prior to the cell immunization. Spleen cells from the immunized mice were harvested and fused with the myeloma cell line. The hybridomas were subcloned and assayed by Cell ELISA for the ability to secrete immunoglobulin that binds to the extracellular domain of FZD10 (amino acid residues 1-225 of FZD10). For cell ELISA, COS-7 cells expressing FZD10-myc/His (the entire coding sequence of FZD10 cDNA and Myc and His epitope tags at its C terminus) were seeded into 96-well plates. Subsequently, 50 μl of the culture supernatants obtained from hybridomas were added to the plate and incubated for 30 minutes at room temperature. After washing the cells, goat anti-mouse IgG-POD (Medical and Biological Laboratories, Nagoya, Japan) was added at 1:10000 dilution, incubated for 30 minutes at room temperature. Bound antibodies were detected at OD₄₅₀₋₆₂₀nm. Positive clones were further analyzed for specific binding activity. These clones includes: clones 39-2 and 39-10 (disclosed in WO2005/004912, referred to as 5F2) as well as 92-13 and 93-22. All Mabs were of the IgG2a isotype as determined by means of the IsoStrip Mouse Monoclonal antibody isotyping kit (Roche). The Mabs were affinity purified on protein G-sepharose for further characterization.

The hybridoma clone 93-22 producing mouse monoclonal antibody 93-22 was deposited by Shuichi Nakatsuru internationally at the IPOD International Patent Organism Depository of the National Institute of Advanced Industrial Science and Technology (AIST Tsukuba Central 6, 1-1, Higashi 1-chome, Tsukuba-shi, Ibaraki-Ken, 305-8566 Japan) as of Jun. 14, 2006 under the deposit number of FERM BP-10620. Also, hybridoma clone 92-13 producing mouse monoclonal antibody 92-13 was deposited by Shuichi Nakatsuru internationally at the IPOD International Patent Organism Depository of the National Institute of AIST as of Jun. 28, 2006 under the deposit number of FERM BP-10628.

(2) Labeling Antibodies with Radionuclides

¹²⁵I-labeled Mabs were prepared by chloramine T method (Arano, Y., et al. (1999). Cancer Res, 59, 128-34.). 740 kBq/2 μl of Na¹²⁵I was added to 10 μg of Mab in 100 μl of 0.3M sodium phosphate buffer. One μg of chloramine-T in 3 μl of 0.3M sodium phosphate buffer was further added, incubated for 5 min at room temperature. Labeled antibody was purified using Biospin column 6 (Bio-Rad).

For labeling Mabs with ¹¹¹In, 1 mg of Mab in 100 μl of 50 mM borate buffer (pH8.5) was conjugated to isothiocyanato benzyl diethylenetriaminepentaacetic acid (SCN-BZ-DTPA; Macrocyclics) in dimethylformamide at molar ratio 1:3. After incubation at 37° C. for 20 hours, Mab conjugates were purified using Biospin column 6. 40 μl of ¹¹¹In was incubated in 60 μl of 0.25M acetic acid buffer (pH5.5) and incorporated into 10 μg/μl of Mab-DTPA conjugates for one hour at room temperature. Labeled antibody was purified using Biospin column 6.

For generating ⁹⁰Y-conjugated 92-13, 92-13 was conjugated with DTPA to lysine residues. DTPA-92-13 was labeled with yttrium to a specific activity 100 μCi/mg, and the immunoreactivity of the ⁹⁰Y-DTPA-92-13 was approximately 70%.

(3) Synthesis of Alexa647-Labeled Mabs.

Labeling Mabs with Alexa-Fluoro647 was carried out according to manufacturer's instruction using Alexa647 Monoclonal Antibody Labeling Kit (Molecular Probes, Eugene, Oreg.). The Alexa647 reactive dye has a succinimidyl ester moiety that reacts with primary amines of proteins, and resulting Mabs-dye conjugates were purified by size exclusion column.

Example 2 Binding Activities of Anti-FZD10 Monoclonal Antibodies

The present inventors applied two methods for evaluation of the binding affinity of mouse-monoclonal antibodies; flow cytometrical analysis with fluorescent dyes and radioactive measurement using ¹²⁵I.

(I) Flow Cytometry (FACS) Analysis

To investigate the cell-binding affinities of the four antibodies, 39-2 and 39-10 (disclosed in WO2005/004912), 92-13 and 93-22, we performed flow cytometry (FACS) experiments. For flow cytometrical analysis with indirect fluorescence, suspensions of 5×10⁶ cells were incubated with 10 μg/ml of Mabs or non-immunized mouse IgG (Beckman Coulter) for 30 min at 4° C. After washing with PBS, 2 μg of fluorescent goat anti-mouse IgG (Alexa Fluor 488, Molecular Probes, Eugene, Oreg.) was added, and the cell suspension was incubated for 30 min at 4° C. for analysis by FACScan (Becton Dickinson, Franklin Lakes, N.J.). For direct immunofluorescence assays, cells were incubated with 2 μg of Alexa488-Mabs in the presence or absence of excess amount (100 μg) of non-labeled Mabs for 30 min at 4° C. and subjected to analysis by FACScan.

In order to confirm the expression of FZD10 in cell lines, we performed RT-PCR. For RT-PCR experiments, total RNAs were extracted from cell lines using TRIzol reagent (Invitrogen, Carlsbad, Calif., USA), and 3 μg aliquot of each total RNA was reversely transcribed. PCR amplification was performed using the cDNAs as templates with the following primers: 5′-TATCGGGCTCTTCTCTGTGC-3′ (SEQ ID NO: 9) and 5′-GACTGGGCAGGGATCTCATA-3′ (SEQ ID NO: 10) for FZD10 and 5′-TTAGCTGTGCTCGCGCTACT-3′ (SEQ ID NO: 11) and 5′-TCACATGGTTCACACGGCAG-3′ (SEQ ID NO: 12) for β2-microglobulin (β2/MG), the internal control.

As shown in FIG. 1 a, all of four Mabs, 39-2, 39-10, 92-13 and 93-22 bound to four FZD10-expressing SS cell lines, SYO-1, YafuSS, HS-SY-2, and Fuji in FZD10-dose dependent manner, but not bound to two cell lines, 1973/99 and LoVo, in which no transcript of FZD10 was detected. Table 1 below indicates correlation between relative Mean fluorescent Intensities (MFI) of these Mabs and the expression levels of FZD10 shown in FIG. 1 b. In addition, particularly, we demonstrated that 92-13 and 93-22 Mabs also bound to the SNU-C5 transfected with FZD10-myc/His construct, while no binding was detected with SNU-C5 cells transfected with empty vector (FIG. 1 c), suggesting specific binding of those 92-13 and 93-22 Mabs against FZD10 protein.

TABLE 1 Binding of anti-FZD10 mAbs to human SS cell lines SYO-1, YaFuSS, HS-SY-II, Fuji, 1973/99 and human colon cancer cell line, LoVo. SYO-1 YaFuss HS-SY-II Fuji 1973/99 LoVo 39-2 17.6 11.6 9.4 7.1 5.5 1.1 39-10 18.4 11.8 9.9 6.9 4.9 1.0 92-13 4.7 3.0 3.0 1.3 0.9 1.0 93-22 3.3 2.7 2.4 1.1 1.0 1.1 The MFI of FZD10 is measured by flow cytometry as described above.

(2) Binding Activity Against Normal Blood Cells

To confirm whether those antibodies can be applied for clinical use, the present inventors further examined the binding activity of antibodies against normal blood cells. To evaluate the non-specific binding activity of Mabs against normal blood cell, ¹²⁵I-labeled Mabs were incubated with 100 μl of healthy fresh blood. After incubation for one hour at room temperature, the radioactivities of cell pellet were measured as described above.

The binding activity of ¹²⁵I-labeled 92-13 and 93-22 Mabs against normal human blood cells were undetectable in all of three individual donors, whereas those of 39-2 and 39-10 Mabs were detected in all of three individual donors (FIG. 1 d). These results were consistent with those of FACS analysis using human peripheral blood mononuclear cell (data not shown), suggesting clinical applicability of only 92-13 and 93-22 antibodies with little possibility of adverse effect to SS patients because of very specific binding affinity to the FZD10 molecule. Therefore, we focused on only 92-13 and 93-22 antibodies for further analysis.

(3) Additional Analyses

Furthermore, binding assay was performed using ¹²⁵I-labeled Mabs (see Example 1 (2)) to evaluate the binding affinity against FZD10 molecules on cell surface. For radioactive analysis, 0.5 kBq (0.001 μg antibody) ¹²⁵I-labeled Mabs prepared in Example 1 (2) were added to 100 μl of cell suspension with various amounts of non-labeled identical Mabs. After incubation for one hour at room temperature, the cell suspension was centrifuged at 800×g. Supernatant was removed and the radioactivity of cell pellet was measured.

The results showed higher binding affinity of 92-13 antibody than 93-22 antibody; approximately 33% of 92-13 bound to the cells and approximately 9% of 93-22 antibody bound to the cells under the same condition (FIG. 1 e). The amount of the bound antibody decreased as non-labeled antibodies were added in a dose-dependent manner.

We subsequently performed binding competition analysis of 92-13 with 93-22 Mabs using flow cytometry. Cell binding of the both of Alexa488-labeled antibodies were completely blocked by high amount of non-labeled antibodies (FIGS. 1 f, ii and iii) to each other, suggesting that 92-13 and 93-22 Mabs are likely to recognize very similar or same epitope of FZD10. These findings suggest that these Mabs is able to specifically recognize FZD10 expressed on cell surface of SS cells.

Example 3 Immunohistochemistry

To evaluate the binding specificity of 92-13 and 93-22 to human tissues, we performed immunohistochemical analysis using frozen tissue sections. Tissue sections of frozen normal adult human organs (BioChain, Hayward, Calif.) were fixed with 4% paraformaldehyde at 4° C. for 15 min, and incubated with 5 μg/ml Mabs for one hour at room temperature. Subsequently, mouse ENVISION Polymer Reagent (DAKO) was added and visualized with peroxidase substrate (3,3′-Diaminobenzidine Tetrahydrochloride).

The results are shown in FIG. 2. FIG. 2 shows immunohistochemical analyses in SS and normal human frozen tissue sections with no antibody (a, d, g, j, and m), 92-13 (b, e, h, k, and n) and 93-22 (c, f, i, I, and o). (a-c), synovial sarcoma; (d-f), kidney; (g-i), liver, (j-l), heart; (m-o), brain. Expectedly, we observed strong immunoreactivity to FZD10 in SS specimen (FIG. 2, a, b, and c) and placenta (data not shown), but did not detect in normal kidney, heart, brain and liver (FIG. 2, d-o), as concordant with the results of northern-blot and RT-PCR experiments (Nagayama, S., et al. (2005). Oncogene, 24, 6201-6212.).

Example 4 Biodistribution of Anti-FZD10 Mabs in Balb/c Mice Xenograft Model

Distribution of 92-13 and 93-22 in in vivo model was examined in BALB/c mice by means of two independent methods, radionuclide imaging and fluorescent imaging.

(I) In vivo Radionuclide Imaging

In vivo experiments were performed in the animal facility in accordance with institutional guidelines. BALB/cA Jcl-nu mice (female, 7 weeks old) were injected subcutaneously (s.c.) with SYO-1 tumor cells (5×10⁶ cells), in 0.1 ml PBS, in the flanks. For biodistribution studies, mice with fully established tumors were given 10 kBq (0.5-1 μg) of ¹²⁵I-labeled Mabs and 10 kBq (0.5-1 μg) of ¹¹¹In-labeled Mabs via tail vain. At 1, 24, 48 hours, animals were euthanized and the weight and radioactivity of tissues were measured. The distribution was expressed as % of injected dose/g of tissue for all samples. For optical imaging of biodistribution, LoVo-tumor bearing mice were used in addition to SYO-1 tumor mice. LoVo tumor cells (1×10⁷ cells) were injected s.c. into BALB/cA Jcl-nu mice as described above. When tumors were fully established, the mice were subjected to the imaging study.

The results in FIG. 3 a demonstrates that the radioactivity of ¹¹¹In-92-13 associated with the blood decreased from 35% injected dose per gram (% ID/g) at one hour postinjection to 12% after 48 hours. Radioactivities of ¹¹¹In-92-13 associated liver, kidney, intestine, spleen, pancreas, lung, heart, stomach and muscle remained fairly constant or decreasing throughout the observation (FIG. 3 a). Radioactivity of ¹¹¹In-92-13 associated with tumor accumulated throughout the experiment, from 2% ID/g at one hour postinjection to 11% ID/g after 48 hours. On the other hand, FIG. 3 b demonstrates that radioactivity of ¹²⁵I-labeled 92-13 associated with tumor did not increased significantly although blood-associated radioactivity fell from 25% at one hour to 7% after 48 hours and radioactivities associated with other normal organs remained constant. The ¹²⁵I-labeled antibodies were possibly degraded inside the cell after internalization. ¹¹¹In-labeled 93-22 was also accumulated into SYO-1 tumor at 48 hours postinjection (FIG. 3 c) and ¹²⁵I-labeled 93-22 showed poor accumulation (FIG. 3 d), suggesting its internalization as well as 92-13.

(2) In vivo Fluorescence Imaging

In vivo fluorescence imaging was performed with IVIS™ Imaging System 100 series (Xenogen, Alameda, Calif.). An optimized Cy5.5 filter was used to acquire Alexa647-Mabs fluorescence in vivo. SYO-1 tumor-bearing mice were injected 20 μg of Alexa647-labeled Mabs intraperitoneally and subjected to fluorescent imaging at various time points. The mice were fed with food that is not containing alfalfa for four days in prior to injecting Mabs in order to reduce the background fluorescence. When acquiring images, mice were anesthetized with 2% of isoflurane (Abbott Laboratories) and placed in the IVIS system. The mice were euthanized at four days after the Mab injection, the tumor and major organs were dissected, and fluorescence image was obtained.

As shown in FIG. 4 a, significant amount of fluorescence was detected at the location of tumor at 24 hours after the injection. The tumor-bound fluorescence was observed for both Mabs, 92-13 and 93-22; the signals reached at maximum level at about 48 hours after the injection, and could be detectable at 96 hours after the injection. The present inventors sacrificed these mice at 120 hours postinjection and measured their fluorescence intensity in the tumor and also important normal organs (liver, spleen, kidney, pancreas, colon) (FIGS. 4 b and 4 c). Very strong fluorescence signal was observed in the dissected tumor, whereas no fluorescence signal was detected in normal organs. To validate the binding specificity, the present inventors generated xenografts using antigen-negative cell line, LoVo, in nude mice and injected Alexa647-labeled Mabs, performed fluorescent imaging analysis. In LoVo-bearing mice, fluorescent was detected neither at the location of the tumor (FIG. 5 a), nor in the dissected tumor or other organs (FIGS. 5 b and 5 c). These results demonstrated that these Mabs are also able to bind specifically to FZD10-expressed tumor cells in vivo.

Example 5 Internalization of Anti-FZD10 Mabs into Antigen-Positive Cells

To investigate molecular behavior of these Mabs after binding to the cell surfaces, their localization was traced using in vitro imaging system.

Cells were plated into 8-well chamber slides (Nalge Nunc International, Naperville, Ill.) at density of 5×10⁴ cells per well. Cells were incubated with Mabs for three hours at 37° C. in air chamber containing 5% CO₂. Mabs bound to the cell surface were removed by acid stripping buffer (0.1M Glycine, 500 mM NaCl, pH2.5) at 4° C. for 10 min and neutralized with 500 mM Tris (pH7.5). Cells were then fixed with 3.7% formaldehyde for 15 min at room temperature, and permeabilized by exposure to 0.2% TritonX-100 for 10 min, followed by blocking with 3% bovine serum albumin for one hour at room temperature. To detect the Mabs internalized into the cell, samples were incubated with Alexa488-labeled goat-anti mouse IgG (1:700 dilution) for one hour at room temperature. The slides were mounted with DAPI (Vectashield, Vector Laboratories, Burlingame, Calif.) and analyzed under Leica TCS SPI confocal optics.

As shown in FIG. 6, both Mabs 92-13 and 93-22 were efficiently incorporated into the cytosol of SYO-1 cells and YaFuSS cells at 3 hours after the incubation of Mab with cells by confocal microscope imaging detected using Alexa488-labeled goat anti-mouse IgG (FIG. 6, a-f). On the other hand, the fluorescence signals of these Mabs were hardly detectable in LoVo cells without FZD10 expression (FIG. 6, g-i), demonstrating that the specific binding of Mabs to cell-surface FZD10 induced the internalization of the antibodies.

Example 6 Specific Cytotoxity of Mabs

92-13 and 93-22 had no effect on tumor cell growth when added directly into the cultured cell (data not shown). For therapy studies, SYO-1 tumors were grown in BALB/cA Jcl-nu mice in the same manner as in Example 4. The diameters of the tumors were measured by calipers and the tumor volumes were determined using the following formula; 0.5×(larger diameter)×(smaller diameter)² as described previously (Nagayama, S., et al. (2005). Oncogene, 24, 6201-12.). When the tumor volumes reached more than 0.4-2.8 cm³, Balb/c-nude mice bearing subcutaneous SYO-1 tumor were randomly assigned to treatment groups and received intravenous injections of the 100 μCi of ⁹⁰Y-labeled Mabs or control Mabs via tail vain. Mice were weighed and tumor diameters were recorded.

FIG. 7 showed that tumor volumes were markedly reduced immediately after treatment, almost to traces within one week in all mice. When 50 μCi of ⁹⁰Y-DTPA-92-13 were given to the mice, tumors >1 cm³ volumes refracted two weeks after treatment although they showed marked reduction of tumor size immediately after treatment. The mice showed temporary decrease of the weight (10˜15%), however, they recovered in one week and no visible toxic signs were observed (data not shown).

Example 7 Generation of Chimeric Antibodies

Chimeric antibodies corresponding to mouse 92-13 and 93-22 antibodies, ch92-13 and ch93-22 were generated by replacement of the variable region sequence of each mouse antibody to the human IgG₁ constant region under the control of CMV promoter. Total RNAs were extracted from hybridoma clones 92-13 and 93-22. cDNA was synthesized from the total RNA using GeneRacer™ Kit (Invitrogen). The sequences of variable regions of monoclonal antibodies were amplified using forward primer (GeneRacer™5′Primer) and reverse primer; CH1 (IgG2a); 5′-AATTTTCTTGTCCACCTTGGTG-3′ (SEQ ID NO: 3) for heavy chain and CL1 (kappa); 5′-CTAACACTCATTCCTGTTGAAGCTCT-3′ (SEQ ID NO: 4) for light chain. PCR products were sequenced and the sequences coding the m92-13 and m93-22 variable region were determined.

As a result, the amino acid sequence of mouse Ig H-chain variable regions and L-chain variable regions were determined as follows:

-   92-13, H-chain variable region:     MKCSWVIFFLMAVVTGVNSEVQLQQSGAELVKPGASVKLSCTASGFNINDTYMH     WVKQRPEQGLEWIGRIDPANGNTKYDPKFQGKATITADTSSNTAYLQLSSLTSEDT     AVYYCARGARGSRFAYWGQGTLVTVSA (SEQ ID NO: 13) encoded by the     nucleotide sequence of SEQ ID NO: 14, and -   92-13, L-chain variable region:     MSVPTQVLGLLLLWLTDARCDIQMTQSPASLSVSVGETVTITCRASENIYSNLAWY     QQKQGKSPQLLVYVATNLADGVPSRFSGSGSGTQYSLKINSLQSEDFGSYYCQHF     WGTPYTFGGGTKL (SEQ ID NO: 21) encoded by the nucleotide sequence of     SEQ ID NO: 22; and -   93-22, H-chain variable region:     MGWSRIFLFLLSITAGVHCQVQLQQSGPELVKPGASVKISCKASGYAFSSSWMNW     VKQRPGQGLEWIGRIYPGDGDTNYNGKFKGKATLTADKSSSTAYMQLSSLTSVDS     AVYFCARGGNYGWFAYWGQGTLVTVSAGS (SEQ ID NO: 29) encoded by the     nucleotide sequence of SEQ ID NO: 30, and -   93-22, L-chain variable region:     METDTLLLWVLLLWVPGSTGDIVLTQSPASLAVSLGQRATISCRASKSVSTSGYSY     MHWYQQKPGQPPKLLIYLASNLESGVPARFSGSGSGTDFTLNIHPVEEEDAATYY     CQHSRELYTFGGGTKLGS (SEQ ID NO: 37) encoded by the nucleotide     sequence of SEQ ID NO: 38. Underlines indicate the signal sequences.

The CDR (complementarity determining region) sequences of the antibodies were determined as follows:

-   92-13, INDTYMH (SEQ ID NO: 15) as VH CDR1, RIDPANGNTKYD (SEQ ID     NO: 17) as VH CDR2, and GSRFAY (SEQ ID NO: 19) as VH CDR3,     RASENIYSNLA (SEQ ID NO: 23) as VL CDR1, VATNLAD (SEQ ID NO: 25) as     VL CDR2, and QHFWGTPY (SEQ ID NO: 27) as VL CDR3; and -   93-22, SSWMN (SEQ ID NO: 31) as VH CDR1, RIYPGDGDTNYN (SEQ ID     NO: 33) as VH CDR2, and GGNYGWFAY (SEQ ID NO: 35) as VH CDR3,     RASKSVSTSGYSYMH (SEQ ID NO: 39) as VL CDR1, LASNLES (SEQ ID NO: 41)     as VL CDR2, and QHSRELY (SEQ ID NO: 43) as VL CDR3.

In addition, the amino acid sequences of the H chains and L chains of mouse monoclonal antibodies 92-13, 93-22 and 39-10 are determined as follows:

-   92-13, H chain: SEQ ID NO: 58 (encoded by the nucleotide sequence of     SEQ ID NO: 57); -   92-13, L chain: SEQ ID NO: 60 (encoded by the nucleotide sequence of     SEQ ID NO: 59); -   93-22, H chain: SEQ ID NO: 62 (encoded by the nucleotide sequence of     SEQ ID NO: 61); -   93-22, L chain: SEQ ID NO: 64 (encoded by the nucleotide sequence of     SEQ ID NO: 63); -   39-10, H chain: SEQ ID NO: 66 (encoded by the nucleotide sequence of     SEQ ID NO: 65); -   39-10, L chain: SEQ ID NO: 68 (encoded by the nucleotide sequence of     SEQ ID NO: 67).

According to the determined sequence, specific primers for m92-13 variable region were designed: 5′-AATAGCGGCCGCACCATGAAATGCAGCTGGGTTATCTT-3′ (SEQ ID NO: 5) and 5′-AATAGCTAGCTGCAGAGACAGTGACCAGAGTCC-3′ (SEQ ID NO: 6) for heavy chain and 5′-AATAGCGGCCGCACCATGAGTGTGCCCACTCAGG-3′ (SEQ ID NO: 7) and 5′-TTCCAGCTTGGTCCCCCC-3′ (SEQ ID NO: 8) for light chain. Also, specific primers for m93-22 variable region were designed, 5′-AATAGCGGCCGCACCATGGGATGGAGCCGGATCTTT-3′ (SEQ ID NO: 53) and 5′-AATAGGATCCTGCAGAGACAGTGACCAGAGTCCCTT-3′ (SEQ ID NO: 54) for heavy chain and 5′-AATAGCGGCCGCACCATGGAGACAGACACACTCCT-3′ (SEQ ID NO: 55) and 5′-AATAGGATCCCAGCTTGGTCCCCCCTCCGAACGT-3′ (SEQ ID NO: 56) for light chain. To construct the expression vector for chimeric antibodies, two cassette vectors were prepared. The DNA fragment coding human IgG1 (CH1-CH3) was inserted into pQCXIH (Clontech) (pQCXCHIH) and the DNA fragment coding human Igκ (CL1) was inserted into pQCXIP (pQCXCLIP). For obtaining DNA fragments coding human IgG1 or human Igκ, human constant region library was prepared using cDNA from human PBMC (peripheral blood mononuclear cells) by the reported method (Liu, A. Y. et al., Proc. Natl. Acad. Sci. USA, Vol. 84, 3439-43, 1987; Reff, M. E. et al., Blood, Vol. 83, No. 2, 435-45, 1994). The DNAs coding variable region of m92-13 and m93-22 heavy chain and light chain were PCR amplified, sequenced and subcloned into pQCXCHIH and pQCXCLIP respectively using NotI and BamHI site. These vectors were co-transfected into CHO cells. Transfected cells were cultured in F-12 medium containing 500 μg/ml Hygromycin and 10 μg/ml Puromycin. When cells grow sub-confluently, the medium was exchanged to serum-free medium (CHO-S-SFM II; GIBCO) and chimeric antibody was purified from the supernatant of cultured cells using protein A-affinity column (GE Amersham) and was sequenced. The sequence of heavy chain of chimeric antibody ch92-13 comprises SEQ ID NO: 46 encoded by the nucleotide sequence of SEQ ID NO: 45; and the sequence of light chain of chimeric antibody ch92-13 comprises SEQ ID NO: 48 encoded by the nucleotide sequence of SEQ ID NO: 47. The sequence of heavy chain of chimeric antibody ch93-22 comprises SEQ ID NO: 49 encoded by the nucleotide sequence of SEQ ID NO: 50; and the sequence of light chain of chimeric antibody ch93-22 comprises SEQ ID NO: 52 encoded by the nucleotide sequence of SEQ ID NO: 51.

Example 8 Binding Activity of Chimeric Antibodies

Antibody-dependent cell cytotoxity (ADCC) activities induced by chimeric 92-13 and 93-22 were determined using LDH activity as described previously (Nagayama, S., et al. (2005). Oncogene, 24, 6201-6212.). Fresh effector cells were isolated from heparinized peripheral blood of a healthy donor by Ficoll-Plaque (Amersham Bioscience). Effector cells (E) and target cells (T) (each, 5×10³/well) were co-incubated for 6 h at 37° C. in quadruplicate at various E:T ratios, together with chimeric 92-13, chimeric 93-22 or non-immunized human IgG, in 0.1 ml of phenol red-free RPM! 1640 supplemented with 5% FBS in a 96-well plate. LDH released in the culture supernatants was determined by absorbance at 490 nm. The percentage of specific cytotoxicity was calculated according to the manufacturer's instructions.

Referring to the effector activity, both chimeric 92-13 and 93-22 induced ADCC specifically to the FZD10-overexpressing SYO-1 cells (FIG. 8, a and c), but not to the FZD10-negative LoVo cells (FIG. 8, b and d). Particularly, chimeric 92-13 showed higher induction of cytotoxity as compared with chimeric 93-22; however, their activity depends on effector cell donor, possibly caused by polymorphism of Fc receptor.

Each of the applications and patents mentioned in this document, and each document cited or referenced in each of the above applications and patents are hereby incorporated herein by reference. Furthermore, all documents cited in this text, and all documents cited or referenced in documents cited in this text, and any manufacturer's instructions or catalogues for any products cited or mentioned in this text, are hereby incorporated herein by reference.

Various modifications and variations of the described methods and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments and that many modifications and additions thereto may be made within the scope of the invention. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in molecular biology or related fields are intended to be within the scope of the claims. Furthermore, various combinations of the features of the following dependent claims can be made with the features of the independent claims without departing from the scope of the present invention. 

1. An antibody or a fragment thereof, which comprises an H (heavy) chain V (variable) region comprising a complementarity determining region (CDR) having the amino acid sequences shown in SEQ ID NOs: 15, 17 and 19 or a CDR functionally equivalent thereto and an L (light) chain V region comprising a CDR having the amino acid sequences shown in SEQ ID NOs: 23, 25 and 27 a CDR functionally equivalent thereto, and which is capable of binding to a Frizzled homologue 10 (FZD10) protein or a partial peptide thereof.
 2. The antibody or fragment thereof according to claim 1, wherein the antibody is selected from the group consisting of a mouse antibody, a chimeric antibody, a humanized antibody, an antibody fragment, and single-chain antibody.
 3. The antibody or fragment thereof according to claim 1, wherein the antibody is a mouse antibody.
 4. The antibody or fragment thereof according to claim 3, wherein the mouse antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 57 and/or an L chain having the amino acid sequence shown in SEQ ID NO:
 59. 5. The antibody or fragment thereof according to claim 3, wherein the mouse antibody is produced by the hybridoma clone 92-13 (FERM BP-10628).
 6. The antibody or fragment thereof according to claim 1, wherein the antibody is a chimeric antibody.
 7. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO:
 13. 8. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO:
 46. 9. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody comprises an L chain V region having the amino acid sequence shown in SEQ ID NO:
 21. 10. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody comprises an L chain having the amino acid sequence shown in SEQ ID NO:
 48. 11. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO: 13 and an L chain V region having the amino acid sequence shown in SEQ ID NO:
 21. 12. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 46 and an L chain having the amino acid sequence shown in SEQ ID NO:
 48. 13. The antibody or fragment thereof according to claim 6, wherein the chimeric antibody further comprises a human antibody C (constant) region.
 14. The antibody or fragment thereof according to claim 1, wherein the antibody is a humanized antibody.
 15. The antibody or fragment thereof according to claim 14, wherein the humanized antibody further comprises a human antibody FR (framework) region and/or a human antibody C region.
 16. An antibody or a fragment thereof, which comprises an H (heavy) chain V (variable) region comprising a complementarity determining region (CDR) having the amino acid sequences shown in SEQ ID NOs: 31, 33 and 35 or a CDR functionally equivalent thereto and an L (light) chain V region comprising a CDR having the amino acid sequences shown in SEQ ID NOs: 39, 41 and 43 a CDR functionally equivalent thereto, and which is capable of binding to a Frizzled homologue 10 (FZD10) protein or a partial peptide thereof.
 17. The antibody or fragment thereof according to claim 16, wherein the antibody is selected from the group consisting of a mouse antibody, a chimeric antibody, a humanized antibody, an antibody fragment, and single-chain antibody.
 18. The antibody or fragment thereof according to claim 16, wherein the antibody is a mouse antibody.
 19. The antibody or fragment thereof according to claim 18, wherein the mouse antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 61 and/or an L chain having the amino acid sequence shown in SEQ ID NO:
 63. 20. The antibody or fragment thereof according to claim 18, wherein the mouse antibody is produced by the hybridoma clone 93-22 (FERM BP-10620).
 21. The antibody or fragment thereof according to claim 16, wherein the antibody is a chimeric antibody.
 22. The antibody or fragment thereof according to claim 21, wherein the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO:
 29. 23. The antibody or fragment thereof according to claim 21, wherein the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO:
 50. 24. The antibody or fragment thereof according to claim 21 wherein the chimeric antibody comprises an L chain V region having the amino acid sequence shown in SEQ ID NO:
 37. 25. The antibody or fragment thereof according to claim 21, wherein the chimeric antibody comprises an L chain having the amino acid sequence shown in SEQ ID NO:
 52. 26. The antibody or fragment thereof according to claim 21, wherein the chimeric antibody comprises an H chain V region having the amino acid sequence shown in SEQ ID NO: 29 and an L chain V region having the amino acid sequence shown in SEQ ID NO:
 37. 27. The antibody or fragment thereof according to claim 21, wherein the chimeric antibody comprises an H chain having the amino acid sequence shown in SEQ ID NO: 50 and an L chain having the amino acid sequence shown in SEQ ID NO:
 52. 28. The antibody or fragment thereof according to claim 21, wherein the chimeric antibody further comprises a human antibody C (constant) region.
 29. The antibody or fragment thereof according to claim 16, wherein the antibody is a humanized antibody.
 30. The antibody or fragment thereof according to claim 29, wherein the humanized antibody further comprises a human antibody FR (framework) region and/or a human antibody C region.
 31. The antibody or fragment thereof according to claim 1, which is labeled with a radioisotope label or a fluorescent label.
 32. The antibody or fragment thereof according to claim 31, wherein the radioisotope label is selected from ⁹⁰yttrium (⁹⁰Y), ¹²⁵iodine (¹²⁵I) and ¹¹¹indium (¹¹¹In).
 33. A hybridoma clone 92-13 (FERM BP-10628) which produces the mouse monoclonal antibody 92-13.
 34. A hybridoma clone 93-22 (FERM BP-10620) which produces the mouse monoclonal antibody 93-22.
 35. A method for treating or preventing a disease that is associated with Frizzled homologue 10 (FZD10) in a subject, comprising administering to the subject an effective amount of the antibody or fragment according to claim
 1. 36. The method according to claim 35, wherein the disease that is associated with FZD10 is selected from synovial sarcoma (SS), colorectal cancer, gastric cancer, chronic myeloid leukemia (CML), and acute myeloid leukemia (AML).
 37. A method for diagnosis or prognosis of a disease that is associated with Frizzled homologue 10 (FZD10) or of a predisposition to develop the disease in a subject, comprising (a) contacting a sample or a specimen from the subject with the antibody or fragment according to claim 1; (b) detecting the FZD10 protein in the sample or specimen; and (c) judging whether or not the subject suffers from or is at risk of developing the disease based on the relative abundance of the FZD10 protein compared to a control.
 38. The method according to claim 37, wherein the disease that is associated with FZD10 is selected from synovial sarcoma (SS), colorectal cancer, gastric cancer, chronic myeloid leukemia (CML), and acute myeloid leukemia (AML).
 39. A method for in vivo imaging of Frizzled homologue 10(FZD10) protein in a subject, comprising administering to the subject an effective amount of the antibody or fragment according to claim
 31. 40. A pharmaceutical composition for treating or preventing a disease associated with Frizzled homologue 10 (FZD10), comprising the antibody or fragment according to claim 1 and a pharmaceutically acceptable carrier or excipient;
 41. A kit for diagnosis or prognosis of a disease associated with Frizzled homologue 10 (FZD10), comprising the antibody or fragment according to claim
 1. 42. A pharmaceutical composition for in vivo imaging of Frizzled homologue 10 (FZD10) protein, comprising the antibody or fragment according to claim
 31. 